150's seem to be.......
The default on most boats with roller furlers. The problem is, like you've experienced, over 15 and the boat becomes overpowered and difficult to steer (not to mention scary). Most Furling systems and most sails are not that good at reefing, so reeling in half of the 150 is of almost no use. You can order sails designed to reef well on a furler. The prevailing conditions you sail under should determine your genny size; if you sail under 12kts almost always, a 150 is a good choice. The type of rig and sail plan are also involved. Some fractional rigs perform best with 90-110 jibs. If you're sailing in primarily 15kts or more, a 120 or so might be a better, more comfortable choice. In lighter winds you can always haul up a drifter or cruising spinnaker.
