I agree that sailing is colder (or at least feels that way) than skiing.

One thing I learned in years of spring/cave diving is that there is no such thing as a gasket that won't leak. With the neck, it's due to the constant head turning. With the arms, it's the flexing of the forearm (when working sheets and tillers).

I prefer some sort of wicking undergarments, and then layer on the fleece before entering the drysuit. The wicking keeps the skin surface dry, and fleece can stay warm(er) even when wet. I think wool is the only other thing that claims this - and it's heavier.

I'll be picking up another dry-suit (Kokatat most likely) this year, and certainly will add the relief zipper. I'm still debating about the booties/no booties design...

AND DON'T FORGET A NICE HOOD. Gill has a nice one that's fleece. It's form fitting, fleece, and not as tight as a diving hood... Still experimenting with this though...