I dunno if you're ever going to hit 35mph with two guys and gear and only 50hp, but as noted IF you are going to try another prop, you should go down an inch (maybe even two) in pitch to try to get full-on WOT rpms a little higher into that 5000-6000 range for that motor, if only to extend its life.
According to prop slip calcs, if you've got a 1.85 gear ratio (from web searching), a 14p prop, hitting 32mph at 5200rpm, that's 14% slip...which is not great, but not terrible, I'd want to see closer to 10-11% on a fairly lightweight planning hull. You might try moving the motor up a little on the transom (what folks here call the "x-dimension"), maybe 3/4" to 1.5", to try to reduce lower leg drag. This could both improve slip percentage and increase WOT rpms...just make sure you don't go so high you lose "bite" on the water (and thus, control)!
If it was me, I'd want it to hit ~5800-6000 rpm WOT with a light load, and at least 5500rpm WOT with the heaviest load you'd run in that boat. And if you can find a single prop that'll do both AND give the holeshot, "get-on-plane-ability," and control you want under both conditions, you win! Speed (mph) would be a secondary consideration IMO.
(Basically, if you want considerably more speed, you'll need more hp!)
EDIT: BTW, do you have power trim? Did you optimize it while underway to get the numbers reported above? If no power trim, have you played with (fixed) trim settings?