Does the weight & density drop during the curing process?

If so, about how much should I expect it to change?

The cure has nothing to do with density or weight of your buds. Hanging them gets it nice and dry, but not evenly. The cure is to evenly distribute the remaining moisture in the buds so they smoke good and evenly. It also helps bring out the terpene profile of what ever strain it may be. Technically, bud will lose some weight every time you open your jar-it's just not going to register on a scale.

If your worried about experiencing some dramatic decrease in density and weight from curing your buds...dont' be

The buds do harden up quite a bit with a good cure, making it seem more dense, when you go about holding them after this the illusion that there heavier is sometimes there as well.

Thanks guys, very helpful