I don't pretend to be an expert, but in our experience provided the breeze is anywhere aft of a beam reach our big overlapping genoa wafts us along at a rate of knots that isn't much less that if we'd hoisted the main as well...
Yes, you have to accept that it's unbalanced, but it's a nice compromise to let it out like a roller blind and just roll it back in a your destination.....
I guess we're a bit lazy and old as we do this quite a lot.........Bill.