I have used a harveys 3mm full suit. i had seals in it and had to deliberately flood the suit to get water in it at the neck, that is how water tight it is. very very warm in 60's water.I do know about the flexibility and lead needed differences. I just would like to extend my diving season other than just july august locally. i haven't really considered a drysuit because of the price point. I am going to reach out to local stores this week and see what brands each carries to try these on if at all possible. If not Leisure pro has a good return policy on items that don't fit.