One of the biggest errors was that the bolt rope in the shelve is a
limiting factor to proper lower sail trim. I'm getting better sail trim
on my new sail. Enough to question the effectiveness of the shelve.

I'd be willing to bet your old main just ended with a bolt rope at thefoot and
did not contain a shelf foot. With a proper shelf foot the sail trims
perfectly all the way down to the boom. Without a shelf foot the sail just
rolls into the boom.
S/V Express 30 "Ringmaster"
Trains are a winter sport