Lewis You addressed your post to John and Carmen. Here are some of my thoughts and personal experiences related to a fascinating subject. Please note this post is not a reply on behalf of John or Carmen. Your grounding and centring exercises in PP1 are a good idea.  I would add PP3 to exercise where you have clear representation of PP1 (self) PP2 (model). You can then make any further refinements in your physiology calibrated from PP3.  If you can get another person to work with (other than the model) even better. The extra person can assist you as a coach in ensuring what you return to a clean PP1 only with what you need. I have heard of people who have picked up physiological symptoms of the model when conducting a modelling project using DTI. These cases seem to occur through extensive deep trance identification over a period of time. I would say - the extent of physiological symptom one could potentially pick up is dependent on the depth of "trance" and/or the number of times you do the DTI.  Specific portions of Whispering in the Wind refer to establishing an involuntary unconscious signal.  I would suggest playing with this notion sufficiently to the degree that unconscious signal is operational and able to bring to your conscious attention situations where the activity you are conducting in DTI or PP2 is unecological for your physical or mental health. What I am suggesting is your unconscious signal is able to override PP2 and DTI in certain cases- with the frame maintaining your well being. One could argue that if the unconscious can override a DTI bringing you back to your own set of filters - that the DTI was not pure i.e. fully in the filters of the subject. I say that a signal of this kind can be set up so that it occurs in a specified set of circumstances i.e. if the behaviour does not fit with your physical health.  In modelling - I think a lot depends on how you set the frame - and the purpose of the modelling project. An example of this happened today at course I was running. The participants were asked to model specific skills inherent in certain people in the group. There was guy on the course who is blind and as a consequence has amazing auditory sensory acuity. He can tell who people are based on what he calls the tone of their breathing and the rustle of their clothes. Steve (the blind guy) was in a group with 3 other people. His colleagues were eager to commence the modelling. I asked what their outcome and frame was - their various replies equated to they wanted to model blind person’s auditory skills. I questioned the value of this frame on the basis that the frame may not be ecological or useful. The chances of them requiring all of Steve's skills are remote unless they have impaired vision or intended going around with their eyes closed. The frame was changed to "model Steve's ability to make auditory distinctions" on the basis Steve's vision impairment was idiosyncratic. Having said the above, the person doing the unconscious uptake - did commence with her eyes shut and got to level of competence were she could calibrate different states in another person purely on auditory distinctions (listening for breathing shifts) with the same level of accuracy Steve demonstrated in the exercise. The lady doing the unconscious uptake was amazed as this was a skill previously she said she would not have not thought possible for her. One of the key elements in Steve's behaviour was rapid and small left to right eye movements (flickers). The group also reported foveal hearing -in the sense of being able to delete auditory input not relevant. The group are still working on the project - so far they have coded 7-9 distinctions in breathing patterns including tone (the level of whistle present in the breath) which I found fascinating. The point I am making is the group will use these new auditory distinctions accompanied by their visual sense which is something Steve for obvious reasons is unable to do. I personally felt that setting frame the way they  did -was very important i.e to model the auditory acuity not vision impairment.  The reason why I write the above is to point out something I consider essential in modelling and that is the frame you set yourself. For me this is an important step in preparing yourself for the modelling. Regarding picking up physiological symptoms -  this can also occur in change work. What I write below is personal example and not a recommendation.  A few months ago I was working with a chap on with a specific issue related to confidence in the context of public speaking. The chap also happened to be asthmatic. I was not directly working with the asthma. I found out about the asthma in a brief questioning phase were he revealed he had asthma. I was in front of 20 people doing a hypnosis demo- I was in a  know nothing state that included trance. After about 20 minutes I felt a pain in my chest that I would describe now as a tightening in the left lung which caused my breathing to go more shallow. The feeling was not comfortable and my breathing was restricted.  This was a signal to me that I might have gone to far -with the unconscious rapport. My usual unconscious signal in my stomach which suggests to me that I need to pay attention to something was not active and this puzzled me. I did a check with my unconscious i.e whether it would be OK to continue (and be physiologically OK) in the state- I was previously in with the "tight chest" and I received a yes signal from the unconscious.  So I want back to the tight chest state and continued. Further into the work- my chest tightening ceased. I used this as one cue that my work was complete (There were other sensory cues). I finished with a metaphor of a valve knowing how to open and close and release air into a system - I did not specify the system. (I mapped this metaphor from Erickson's well-known base ball glove metaphor he used with a bed wetter) After the work, I did not ask the subject about his own sensations in his chest because he had little recall for the work- and I didn't want to bring too much to his conscious attention - so I will never really know if I "unconsciously picked up his symptoms"  or hallucinated somehow what I thought his symptoms were. (NB after the work I did a ritual in using PP3 and PP1 and checked with my unconscious signal to ensure I was totally clear from any symptoms related to the tight chest). When the chap came back for a practice group -he reported that the work with confidence and public speaking had been effective. He also reported (not at the same time) that he was using is inhaler less). I have heard John Grinder say it took him some time (4 months I think) to set up his unconscious in such a way he was comfortable to model Erickson. (This is my recollection of a statement I heard John make at a seminar-and not a quote from JG). In Whispering John also talks about his initial reluctance to model Milton until he was ready. If John has time- he might clarify in the forum -what he actually did to arrange his filters in way that it was ecological for him to model Ericskon and how he (JG) knew when he was ready. My summary; set up your filters so you only pick up what you want through framing and suggestion through self hypnosis -calibrating back to your unconscious signal. Or have strong unconscious signal that can override PP2 and/or  DTI in the specific contexts related to physical well being. Set a clear frame for your modelling. If you DTI chose your subject wisely as you for the reasons you state in your post.  Regards Michael Carroll