From reading this I gather that you want the entire bait to weigh 1/2 oz. So you have to make up the body of the lure and weigh that along with the hook hangers, hooks, and all split rings. Then see what kind of weight that you have left to play with. What I mean is, if your body and all of your parts come up to 1/4 oz, then you have 1/4 oz. left to play with for the ballast weight of your bait. No knowing what you are making is kind of tough. Some baits, such as jerkbaits, can have more than one weight.
Personally, I would make the bait and get it to work properly, and then worry about the overall weight of the bait.
Skeeter