Prop Help

[Gfunk]

I have a 2001 150 Opti on mine with a 21" s/s prop on it. Runs fine, but I'm only getting about 4,800 rpms at WOT, 39 max mph. I swapped this motor onto this boat and then put a jackplate on it, so I knew I'd probably be looking at a new prop.
Does anyone have a similar setup and if so, what prop are you running? I'm thinking a 17" aluminum would work pretty good and get my rpm's up where they need to be.
Thanks in advance guys.

Now if I only had time to use it.......