Marcruger...I shy away from cloth straps as folks more knowledgeable than I am tell me that cloth straps were not very common in the day.
Yeah, probably; but uncommon doesn't mean unused, and maybe the best thing to try for is to produce the bag with materials at hand. The reason I started to shy away from belt strap, 9-10 ounce is that it chafed and became uncomfortable over the course of a trail walk. Some of the softer cowhides, such as those made to look like elk or buffalo, worked better and doubled up deerskin got the job done also. I sewed it together, wet it, and hung it up with some dead weights to take most of the stretch out of it.
One thing I found that helped that sort of thing was to load up the 9-10 strap with neatsfoot or, better yet, mink or liquid lanolin oil.