Hi Derek,
Yep youv'e got it!
After setting my Impact using this method I can confirm that the model is almost perfect with regards to trim. On the first flight with the model only very small down trim was applied ( approx 1 mm). The model tracked beautifully in all flight angles and the stall produced a very sedate drop of the nose followed by a perfect wings level shallow glide, awsome! The glide speed during landings can be slowed right up without any wing drop. My incidences are; zero down thrust, 3.5 degrees right thrust ( YS140lm - 15x12 APC - 30% wildcat 3DLV fuel ), +0.25 degrees on the wings and zero degrees on the stabs. I have chosen the rear tail servo set up without the tail incidence adjusters, the models c/g came in as close to perfect as you could wish. If you go to the comp-arf.co.uk site that Mark Shroeder has created, you will see the photo's of the set up method I posted earlier, well done Mark!!

Hope this helps.

Happy New Year to you all.

Andy.