The Symphony is speed sensitive for snaps ( at least it is for me). . Having flown it for the past two years in advanced I can say for certain that if my downline speed is too fast and all things being equal I can wrap it up is a pretty wicked snap. But if I slow my entry speed down the snap is very predictable. Also my C.G. is pretty far forward and my incidence is different than most flying Symphony's. Spins are pretty predicatable as well set up properly. I would look at rudder throw as well like Brian suggested. I do a rudder elevator only spin and the rotation is nice and slow and will come out where I want it to.
Good luck with it, the Symphony really is a great flying plane. I will be sporting 2 of them for the 2008 Masters season in D3
Erik