When crocheting winter gloves, I generally use sock yarn or fingering weight wool. The gauge works out perfectly for the small to medium hand size. Medium to large, however, requires either thicker weight or a larger hook.
I had purchased some fingering weight 100% wool at the Yates Farm Yarn sale, but I found that it felt a bit too stiff and scratchy. Next I tried combining it with lace weight alpaca to soften it up. It worked like a charm.
By combining the two, I achieved the gauge I needed for medium/large gloves. Both being natural fibers, the combination should provide the same if not more warmth and still be water resistant. By using 1 strand of forest green wool with 1 strand of medium brown alpaca, the color combination works wonderfully. The wool should also keep the alpaca from stretching out of shape.
It is important to learn the various properties associated with different fibers to make a combination that works. If I had put the wool with cotton, for example, I would not trust that it would retain the water resistant properties. I could have doubled up the wool, but that would not have softened the finished product at all.
Combining yarns can be a fun way to get the properties you want out of your finished crochet project. Trial and error may take some time, but it is well worth the education you will give yourself.