RE: Flight Flex?
Keep it out of the heat, they flop around alot and twist around alot when trying to pull man tricks.
A few people have cut them open and installed some light weight carbon fiber tubing to make the plane more predictable and have had success in doing so.
I have the yak myself and it is a handful do to being very unpredicatable.
I plan on taking an exacto knife to it very soon.