Barb (as always!) hit the nail right on the head.
One fruit (same one) same time all week. Boring, I know, but once you know how it affects you, you will be able to do whatever you want. So add things slowly and one at a time so you get a feel for how they react. Try a low GI fruit first (berries are great) and if it goes well, try a higher GI fruit next time. If you've tried several different kinds of fruit from all levels of GI numbers, you can probably safely assume that you'll react similarly to most other fruit and stop testing them. Does that make sense?
Good luck...I know you'll love P2!!!