Reducing the weight would be hard, just because the weight is so securely molded in with the bait. You could add weight by sliding a teardrop type sinker over the hook shank before pushing it through the back of the bait.

5 fish per bait sounds about right as far as how long they last. I've seen them last longer and I've seen them get torn nearly in half on one fish. Kind of a crapshoot on the durability, but if you got a dozen fish on one you'd be doing good.

The only other weedless swimbait that comes to mind is the SR Plastics SR7

http://www.calfishing.com/reviews/swimbaits/sr_plastics_sr7/index.html

If you put a G-Mag hook in that bait, it fishes like a mission fish pretty much.

Other option is to take a standard Big Hammer tail and rig it on a weedless jighead. It doesn't look that great presentation wise but it works well at night. I caught this 9.3 last year on a rig like that. It was just something that came to mind when I was getting stuck in the weeds a lot with the regular hammerhead. The jighead in the pic is a yamamoto jig head, 5/8oz

http://www.calfishing.com/gallery/d/316-2/aag.jpg