Well, I think I just realized something. When it comes to my jumping, most of my force is coming from the swinging of my arms, not the pushing of my legs. At least that's what it feels like. I say this because I held a weighted 12 lb. ball above my head, and I had to jump up and tap the rim with it 25 times in a row. I had to do three sets, resting between each set. Oddly enough, the most I did was 16 times, and I progressively did less each time. Furthemore, I feel like I jump way higher on an alley oop than when I'm dunking off the dribble because I can focus more on swinging my arms...honestly, I never thought jumping could be so complex! I guess I just never realized how much I relied on my arms, haha.
Oh, and if it's any indication of progress, I can finally graze the rim with the top of my head now. :) At 6'4", I think that's pretty decent.