I always race Master's when doing TTs, and category when racing on the road (we don't have enough women for that half the time, never mind addind a master's category there).

As Eden said, in a TT, it doesn't matter as much. I do it this way because I've won the Master's category for 2 years running, and the payout is nice. I still usually finish 2nd or 3rd overall, so can see where I stack up against the others.

Good luck!

SheFly