First of all, a half gram of wax per bowl is WAY too much. You're losing more of the product than you're intaking because the wax continues to burn and melt once it's lit, draining into the bottom of your piece. Secondly, would you take a half gram dab? The answer is probably no if you're not a regular/intensive BHO consumer. Anyway, onto solutions...
If you're using a bong, put some ice down the neck. Put small amounts of wax on your bowl and add more if you so desire. This will also prolong the act of smoking which is a bonus for me; I love sitting and conversing with friends over bowl after bowl. Take several small hits in succession. As I said before, the wax burns quickly so by taking small hits that don't kill your lungs, you'll be able to rebound and hit it sooner (therefore you won't waste as much product).