Ben --
Yes, I've had this problem as well, especially as I've frostbitten my fingers a few times over the years. There is a lot under the tuiliq. So, I've done a couple of things: 1/ I had the forearms of my winter tuiliq recut for more volume, though the wrists are the same. 2/ I've trimmed the wrist gaskets of my drysuit just a little so that I can pull them up just slightly higher on my arms and not under the tuiliq gaskets; 3/ I've cut off the cuffs that Kokotat insists on putting over the wrist gaskets; and 4/ I pull up the sleeves of my bunny suit that I wear under my dry suit so that they end near the elbows. (I'm thinking of cutting the sleeves of the bunny suit at the elbows...but haven't so far.) With the changes, there's nothing under wrists of the tuiliq. Much better.
The problem I'm having is sweat. We're padding in among the bergy bits this winter, and are iced out of a few normal launching points. The water at the surface is near or below freezing, though it's about 38-40 degrees just a foot below the surface. I'm paddling in a custom skin-out Brooks tuiliq with a drysuit under. Surgical gloves under Brooks mittens on my hands. I wear a 200-weight fleece 1-piece bunny suit under the drysuit. My sessions always start with some rolling practice to get used to the water temperature. This getup is just fine, warm and comfortable once my face and thumbs get accustomed. But once I get paddling, I perspire. By the time I've paddled for even a short time, the bunny suit starts to wet out. And by the time I'm off the water, the inside of the drysuit is quite wet. (The outside is dry.) It's fine when I'm moving. It wouldn't be OK if I had to be out of the kayak for any period of time, in the water or out.
So now I'm wearing a thin (2mm), very stretchy, skin-out neoprene full wetsuit as a base layer. It mostly works well as a vapor barrier to keep the perspiration out of the insulating bunny suit. This is a Camaro wetsuit that's made for water skiers, I think. There is some water vapor getting out of the vapor barrier through the back zipper that's not watertight. But other than that, this works remarkably well. It also has the added benefit of letting me wear a thinner insulation layer under my drysuit, and so is somewhat more comfortable. The inside of the wetsuit gets soaked inside, though I barely notice that; the insulation layer and the inside of the drysuit stay mostly dry; damp up my back along the zipper.
Have other people had similar issues? Has anyone else tried vapor barriers?
-- Dan Segal