I find this information is invaluable! Thanks for putting it together!
On a side note, GPC is redesigning their backpack for the P3. I really like the pack as it has flown with me as a carryon and many hikes. Seems a shame that it wouldn't work for the new bird.
I pulled out my old GPC backpack for Phantom Vision, and it fits the P3 fine. No cutting or modification is needed. Thought I'd pass that on for anyone who already has this backpack.