What is the best material , wool, silk, ? and least bulky?

What is a good brand?

others here may have a different experience - but i couldn't get them to work; unless your glove is so baggy to begin with that there's plenty of room for a liner, the fit is too tight, no air gets trapped and there's little benefit. New gloves are the answer i'm afraid...

I have Held Phantoms. When the weather gets to be below 50F I break out the silk liners and they work OK. But, I haven't tested them below 40F.

A fair few times when the temperature has dropped whilst I've been at work. I just stuck on a pair of those Latex "saftey" gloves that you may/may not wear when working on your bike/car/whatever to stop your hands getting dirty. They're good at keeping the wind chill off, but can make your hands sweat, depending which ones you use. Obviously not a permanent solution though.