Yeah, the boom will always need help in light air, and will never need help in heavy winds. Its the in-between where I think a lighter line might be beneficial.

The original equiptment list in the Manual calls for 60 feet of 3/8" line.

Most of the mainsheet ends up on the cockpit sole, getting stepped on and grubby, eventually tangled around the tiller head fitting. I'm trying to figure out a solution to that which doesn't require good housekeeping.