In all honesty, when my RSI starts acting up from too much mousing, I just wrap it tightly with an Ace bandage and keep going.  Mine is largely in the back of my hand and forearm.  But I have been to the doctor for it, so I know it's not a symptom of something else.  My doctor actually told me I shouldn't use my right arm at all until all pain and swelling went away.  He said I should put it in a sling if I had to.  Not practical.  Try drinking left handed.  lol.

I can't shell out the cash for a custom made work station, so with long arms and a short torso, I'm pretty much screwed there.

Good luck, and go to the doctor!!

One goes into the house of eleven eleven times, but always comes out one. -River Tam