Paul,
Usually, more rake = more bow lift. It is my observation that the Mercury Cleavers tend to have more rake than most other cleavers. That's one of the reasons I like them so much - they give good stern lift and provide some bow lift as well. If you like the Mercury Cleavers, your best bet is to have Mercury Racing work on it for your specific application. They never let us down, and we just received our 32P Mercury Cleaver from Mercury and ran it this past week for the TV shoot at 115 mph (still had more to go) - no problem!
I have a very high-rake Spinelli Cleaver, but that prop has major work done on it for Formula One use, so it's not a fair example of Spinelli props. It gives a LOT of bow lift though! I'm saving that one for my Progression 22 / 300X that's being built this summer.
Greg