I'm on the light end of a Grande (I'm 6'3" 185) and at first my bow felt very "floaty".....like it was going wherever it wanted and I couldn't do a damn thing about it.  It would get to drifting to the right, I'd slam corrective left backstroke (or a wide, sweep stroke on the right), and it would take it a good 3 seconds to come back where I needed it.  I moved the seat forward ONE notch and I like it much better.  The bow feels like an extension of my body and I'm not fighting against my boat anymore.  

I have heard people say to crank it all the way back so you can work those small chines, but I can't imagine that.  Just different preferences, I guess.