I'm 5'11 x 235 and I ride a 6'3 x 20.5 x 2.75 Lost Mini Driver. Something like this will work for what you're looking for. Get it in Hydroflex PU if you want it to be sturdier than standard PU. I kinda regret I did not go shorter.
5' 9" 200 lbs. just got an epoxy 6' 0" ...Lost monkfish down in Florida this spring. Love it.
I'm 6.0@195 lbs my 6.4firewire dominator floats my fine.even with full suit and all the winter gear.you can go on the FireWire website to find your volume range. If you buy a poly board it might be different. Epoxy seems more buoyant.
Have you ever contacted Eavey? His little simmons type shred sleds look really fun. Not sure how his prices are, though.
I'm 6' 0 220 and ride a 6'0 thing and 5'8 superbuzz from Stretch. Talk to the man himself and he'll get you dialed in, his craftsmanship is amazing.