I am sorry for intruding on this discussion, since the only callouses I get these days are from knitting chainmail (yes, chainmail)... but I would like to offer the following advice based on my experiences.
First:
Oz of Prep vs Lb of Cure; Stretch each of the muscles gently from the forearms to your fingers before you work. A lot of hand and finger pain it actually due to tightened tendons and muscles in the forearms. Even a little bit of this will make a big difference. If you are wondering if YOU need to do this ask yourself if you are always trying to stretch them out afterwards...
Second:
Many of my students found that they could reduce the after effects of a lot of hand/finger use if they increased their water intake before hand. My doctor confirmed that mild dehydration can exasperate arthritis and stiff older joints, and that especially in the winter when heaters are drying folks out indoors, the problem gets worse.