I think the Ratchamatics are awesome myself and use them on every boat I have had since they came out.
On my F16 I am using the 8:1 Ratchamatic with 1/4" mainsheet. Sounds small,but with the 8:1 purchase it is easy to sheet and it also runs out very well when you ease the sheet.

I know in days of yore, we may have used as large as 7/16" line, and for sure 3/8" But with the new advanced blocks it is really not necessary and smaller line works really well.

I even use 1/4" on the Wave. Great for the puffs and when wheeling around the weather mark. Others are having to pull their sheets through the block, while mine just flys out and the sail is set within a boat length for downwind.
Rick