When I look at a loose footed main that's trimmed correctly it's shape just says it's 'right' and more efficient. If sail shape is what it's about a loose footed main has more wind condition options. On the other hand, with a vintage vessel you're changing the look. If you're doing any updating of the look I'd switch to loose footed.
This one is not set correctly and pay no attention to the lazy jacks distorting the sail. You can see what I'm talking about though.
The Admiral looking through the binocs as we approach Ft. Lauderdale after leaving in 2005 for California.