Bustr, the way I work the flaps is to extend them to decelerate and try to get inside the other guy's turn, then raise them as needed for that little bit of E that might be needed. It's a habit that I do in every plane I fly, from the 51 to a 38 to a 190 to a La7. I know that many planes aren't turning 'better' with the flaps extended, but for my style, I try to get slower, get inside the turns, then go from there, and raise the flaps to build some speed.
It's just been my style to get slow, which goes back to AW4W, and when I first started learning a 38. Granted, it was easier back then, and doing it in this game leaves me vulnerable a lot, but it's a habit that came back naturally after being out of the game for a decade.
BnZs, I'll look for some films, but I'm not sure if I have any where I have a pure E advantage. I will check though, and see if I can find some where there is either a noticeable speed or alt. advantage.