That is hard. I have seen people get into 8's at a higher weight than I am now and I have JUST gotten into a 7/8. Of course, I am really short and I have no waist-just boobs and then hips.

Since you are 5'4" I would think you can get into 8's at around 130-135? It also depends on the manufacturer of the clothing. Sizes are not standardized here, so my clothes have all kinds of sizes. In petites, for example, I still wear a size 10-12. Petite sizes are usually sized bigger than regular ones. I also have pants that are size 9's, 10's and 8's that all fit me about the same way. Go figure.