Hi,
I've never tried basswood but I am currently working on a ERC bow that I backed with poplar inner bark. This was some that I retted for making twine and a few of the pieces were wide enough that I thought I would try it as a backing. I glued three layers to it using hide glue, letting each layer dry before I added the next. I have the bow tillered and just need to finish sanding and sealing. The backing is holding up fine so far. Right now I am trying to decide what to use to seal it. The only problem I have seen so far is the fibers on the edge seem like they might lift if something nicked it. A good coating of polyurethane would probably help, but I am trying to keep it as natural as posible. If you have any ideas, I would love to hear them. Once I get it finished I will post some pictures.
Randy