Yeah, also keeping the chin a bit down as well I found out it helps preventing this "overchestation".
Where my mind is though is simulating a hip thrust at the top of the movement, and preparing that top of the movement hip thrust by keeping the glutes contracted throughout the lowering phase of the lift.
The problem is this, though - if you do use the deadlift, RDL, straight leg deadlift, hip thrust, etc etc etc as a glute-oriented exercise, what's left for the hamstrings. I really really want HUGE hamstrings and very strong hamstrings... I know they will continue to work as synergists in all these movements, and that's how they're supposed to work in the first place, but except the glute ham raises and leg curls, I don't know of any direct-ham development exercises.
My belief is that having great calf and hamstring strength would allow me to obtain and maintain a straight leg plant in my one-leg jumps, without all that overload occuring at the knee/knee collapse. That's the most important thing, by far, in the one leg jump at least when dunking is concerned. If you're able to get into that position without collapse then you're only going to be limited by glute power in the hip extension as far as voluntarily applied force is concerned in the jump itself, having the best possible lever (the straight leg).
