I'm not sure what the advantage would be to a dry suit here... and you have to use the head on the boat!
FYI regarding a drysuit alternative, though I can't recall the name of the place but you can see it off to the west of I-95 north of the Hallandale exit, I stopped in to learn about their "custom made" wetsuits. One small modification makes them "dry" (not technically a drysuit but no ocean water touches your skin).
VERY impressive. She's been making them for 20+ years and will demonstrate the compression difference between her materials and "off the shelf" suits with a little tank in the office.
Her zippers are really outstanding, making the suit exceptionally easy to get I/O. For big guys like me they're supposed to be much more comfortable than what's available at DD.
I'm not in the market for a new wetsuit, and when I am I'll go cheap (her's start in the $300 range, maxing out at $500), but if anybody would like to know more let me know and I'll dig her card out.