Which side of the prop blade should be sharpened? The blades on mine are by no means "knife sharp", sharper is better, right?

Yes, the sharper the better...butter knife sharp just won't cut it! No pun intended.

Some good info here:

www.modelgasboats.com/Resource...and_Sharpening/
www.modelgasboats.com/Resource...ving_Your_Prop/
www.modelgasboats.com/Magazine...er_Preparation/
www.modelgasboats.com/Magazine.../Modify_a_Prop/

Gotch ya, LOL! Heated up this one would maybe cut butter! Thanks for the great links Marc and everyone else's help, I,m going to pick up a prop balancer and see what I can do with it. This is my first time doing this so it's good practicing on a cheap prop, I also have a tunnel with an amps 7.5 outboard that could use it too.