We set up our mainsheet to be as short as possible and still be functional. I'll lay the slack across my body and at most the line just kisses the top of the water. You can also try handing the slack off to your skipper, it's not like they are doing all that much, how many hands does it take to hold a tiller? I know it's an imposistion for them but they usually get over it... sort of.
I agree with this. My mainsheet is not an inch too long and when sheeted, there isn't enough slack for it to get out of control. One or two wraps on my hand and I can kick the slack back up on the trampoline with my foot (it can barely get to the water). I've been known to put a longer mainsheet on the boat when distance racing on days that are expected be very windy and very reachy but I haven't done that in a long time.
