Wow, Blabel is speaking of my boat, and is right on!!!
I have an 88 and have a fat seat in the rear, and 3 waterbed tubes, sub box, etc in the nose. While very rarely needed, I also have a fatsac that I can partially fill to balance the boat. Lead plates would be a better alternative.
In my experience, a lower pitch prop will make more difference than the # of blades. Having said that, I run a 4 blade, with a 3 blade as a spare. This will help the holeshot dramatically.
I think what you already have will work fine, several ways:
1. One side sac up front, and one in front of back seat; then put full size sac on top of back seat.
2. Side sacs along engine, and full sac up front 1/2 - 3/4 full.
I personally think #1 will produce a larger wake, but #2 keeps more seating.