I have used my regular summer breathable waders in the winter with additional layers of clothing underneath. The biggest issue for me is my feet getting cold. it would help to have a pair of boots one size larger to allow more socks to be layered under them. I don't think it matters how heavy or thick breathable waders are to keep you warm. What really matters is what you wear underneath them and how much room they have for layering without being too tight. If you pack too much clothing in a restricted space, you cut off circulation and will be colder than if you packed in less clothing.

Ted