How you're not good at one-leg jumping? You looked pretty good to me. It's also much easier to jump with the ball in hand vs. the LR plant jumps that you always try to use when dunking with a ball in hand.
What are your deadlift numbers? I mean, how good are you at posterior chain strength?
ZOMFG , could i be a SL jumper without knowing???

Well , i never practiced much of SLRVJs , maybe if i practiced them they could improve a bit. But as i told you my shins are very sensitive to them , 3-4 max SLRVJs and they start hurting even when i walk!
I feel much more comfortable doing DL jumps , even max runup DLRVJs annoy me , my "natural" prefered style is 1 or 2 steps DLRVJ.
As for jumping for a dunk with the ball in hands , i agree 100% with you , ive posted the same thing when adarq started doing SLRVJs.
I haven't deadlifted for 1,5 year now , back then PR was 268x4 while squat PR was 237x5.