Can you use it as a thumb-rest the same way some people use their std rear brake as a foot rest
Must admit a thumb brake would make my race bike easier to live with! Once I get myself "wedged in" on the saddle I cant move around much and it's awkward for me to get my lickle tootsies back on the footpeg if I move my foot to use the back brake pedal, so I usually ignore it completely on track!
Only ever use the back brake for slow manoeuvres/heavy traffic situations on the road.