I got my OW this past fall and at the end of this month I'm going down to the keys for my first "real" dives. I'm kind of running in circles trying to figure out how much lead to carry. During OW I wore a 3mm shorty and had 14lbs which may have been a bit on the light side as I had trouble staying down when the tank got down to 700psi. That was in fresh water. I'm a big guy 6'4" 360 not grossly obese just a huge frame (Think NFL lineman). When I head down I will be in my Scubapro Knighthawk, henderson thermoprene 5mm full suit, 5mm boots and fins. When I dive in the pool sans wetsuit I'm very negative at 12lbs of lead. I can get by just fine with 6lbs actually. Will the salt and the 5mm wetsuit take that much more lead to get down? I'm diving with rainbow reef. Will they be able to give me a good estimate on what I need when I get there?