Weight in an old Supra?

I have a 1989 Supra Conbrio that is real shallow in the rear & needs weight. Is anyone running one of these with weight in it? I was going to sell the boat for something deeper but decided against it b/c it was cheap, runs good & has a tower (plus it's paid off) I'm a little nervous to start stuffing a 1,000 lbs of weight in it b/c quite frankly it looks like the rub rail would be under the water then The hull is the same as the Comp TSM6 with a real flat hook under the seat. I was thinking of 4 250lb sacks, one on each side of the motor & one front & rear. I'd love to go with more weight but quite frankly I don't think it will handle it, tell me I'm wrong so I can start spending some money Once I get through this I plan on adding a four blade prop for a better pull with the weight.