I have a 3mm normal neoprene suit that's a little tight for me and was thinking about picking up something new. I'm looking at "stretch" type suits like Henderson's Hyperstretch but have heard the stretchniess makes them feel thinner. I'm not sure if I should be getting one in 5mm since I start to get cold around 77F on my second dive in a 3mm fullsuit. Am I crazy for even thinking about that much suit in our waters? What does everyone else dive in?