I carry a Ruger LCR in a Blackhawk ankle rig. I believe it is a size 00. This is an easy and secure rig. The downside is that an ankle rig is not a fast draw rig.
Your environment and possible tactics drive the gear train.
My J frame and Galco ankle glove are becoming my new EDC. Not that I prefer it over my Glock in a belt holster for a defense situation, but there are some places I really can't afford for it to be known I'm carrying and my issued work shirts don't give much opportunity for concealment. A slow draw from the ankle is still better than leaving it at home. My only issue is that it chaps my skin a little after a week of 12 hour days with it on.