makin a blanket is an awesome idea! i just read a anthropologists book about indians in northern california near mt, shasta who used to make blankets out of rabbits. each blanket would have 100 - 300 pelts! you could make it double sided
The domesticated rabbits we are familiar with have thicker skins than their wild relatives, making them better suited for fur-on tanning. With smaller game/thinner hides, some cultures would case skin the animal (removing the skin from the animal in a way similar to pulling a sock off from the top, so that you remove it inside out and have a hide "tube"), then they would cut around it in a spiral, creating a long narrow strip with fur on one side and skin on the other, they would then twist it, so that the skin side turned in on itself and dry it (it isn't tanned, essentially it is a rawhide process, but because it is so thin, it remains pliable/workable, and the skin is twisted in on itself so when it dries it kind of "glues" itself together). They would cut it so that the tail is left on one end and the eye holes are lined up on the other, so the threads could easily be strung together, tail to eye holes, to make a very long rope of fur that could then be used to make a loose knotted blanket/robe/etc. I've done it with several gophers we trapped when I was living on a farm, works well, I could see how with more practice one could make some incredible pieces.
For fur-on tanning, bark tanning is a good process because it will constrict the follicles, preventing the hair from slipping. What is more common is using a salt and alum solution for soaking before braintanning. Alum is a naturally occurring aluminum salt (there's a big mine in the south SF bay area) that helps to tighten up the follicles and cure the hide, but I don't remember very much about the whole process, and have never used it myself.
Could you name the book joaquim? I'm really interested in that type of thing. Survival Skills of Native California by Paul Campbell is a great book. Ishi is fascinating as well, though I haven't delved much deeper into the anthropological material yet. If you're ever passing through the bay area, the Phoebe A. Hearst Museum of Anthropology at UC Berkeley is free and has a small continuing exhibit of Native Californian artifacts, including much of Ishi's material culture. It's definitely worth checking out.