Weighting Question

So I ride in an '05 response lxi, and I'm wondering if you guys could give me some weighting tips. Right now I'm just using a 750# in the back, and then relying on the driver and the passengers for some weight up front, but a lot of the time it's just a spotter. I think i need some more weight up front, and was thinking about putting a 440# in the walkway. Is that going to be too much weight up there? I got bored one day and flooded the ski locker in the middle and that helped it out a little I think, but it bilges out after a while. Any tips?