Unless they have something new, when I called them not too long ago they said they only had a 6.4" water pump pulley and a 6.4" 2-groove crank pulley - so 1:1 ratio. Easy enough to cut the outer groove off on a lathe, but that was considered their "high flow" set-up.
I may have a w/p pulley smaller than that that should work with that crank pulley though. I just wish it wasn't so difficult to come up with a decent single-groove set-up that overdrives the water pump.
When you get a chance, if you could get part numbers, that'd be great! No rush.