Got your PM EJ, but figured I'd post the info here for all.
The cloudraker mitts are indeed seam taped so no need to seamseal. I find them to be sized 1-2 sizes larger depending on your intended purpose. I am a solid size Medium in Outdoor Research Gloves and pretty much wear a medium in all gloves from other brands. With the CloudRakers, I can fit into a size XS if I am only putting my barehand in it without other layers. A size small allows me to put on a midweight fleece glove under. A size medium would allow me to put a puffy mitt under. For those that are curious, here is the corresponding synthetic puffy mitt that MEC sells that is great to layer under http://www.mec.ca/AST/ShopMEC/WomensClothing/GlovesMitts/PRD~5024-115/mec-puffy-mitts-unisex.jsp
Also, if anyone misses the old OR lobster gloves, I found these to be the best replacement
These gloves fit true to size and my mediums only allow a pair of lightweight/medium liners.
I'm sure they can be used fine for winter use, but I would stay away from heavy duty tasks such as shoveling snow...I'd imagine the DWR would break down pretty quickly with such agressive use. I've used my drencher lobster-gloves for cross country skiing with no problems