I have used fingerless rag wool gloves for over 40 years now. I can tell you that they flat work. Not only do they keep your hands warm, but they retain their heat retaining qualities as well.
"A voyage in search of knowledge need never abandon the spirit of adventure."
I have 4 pairs of Buff fingerless gloves, the old style, and one pair with fingers ( my winter pair) looking for a better solution too.......