At 5'6" if you can dunk it is quite an accomplishment. At 5'8" I could dunk a volleyball when I was training for olympic lifting (couldn't palm a basketball) and always considered that impressive (I was 225 though).
Jumping height is not all that is important. You need the proper "dunking technique/timing"... even if you can reach the proper height, reaching it with a ball and trying to throw it down is another story.
Anyway... I would start right now to include 3 neural charge workouts aimed at jumping every week. Prior to the attempt the last heavy lower body workout should be 7 days out, BUT perform some explosive lifts (olympic lifts, jumps squats, etc.) up to 3 days out.
3, 2 and 1 days out perform 2 neural charge workouts per day, aimed at jumping.
It is a volleyball that I will be trying to dunk for the bet (same palming problem).
How would I incorporate the neural charge workouts in with the vertical jump program? Would it be in the morning say, before I do the lower body workouts in the afternoon/evening? What kind of volume should I be doing for these N.C workouts?
Right now I'm just trying to get the height before I start working on the technique. I can get maybe 2 inches above the rim so I have a bit of height to get before I can worry about technique.
I seem to have some of my best jumps after heavy lower body sessions (perhaps a post-activation potentiation thing). Would you suggest something like this for the day of or stick to a neural charge the day before then just a warm-up the day of?
for working on your dunking technique, you could start off with a tennis ball, then move up to a mini basketball before finally going for a volleyball. it'll help you out a lot with reaching your peak vertical right in front of the rim.