Most racers will go with the most sail area they can carry and still maintain optimum heel angles and helm balance. The potentially tighter sheeting angle that can be gained with the blade is probably not a huge consideration, certainly not if it means you are under-powered in the lulls. I would certainly rather be depowering in the gusts than wishing I had more power in the lulls! That goes double if there are waves. Of course that is also assuming that both sails are in good condition and have decent shape!