That's probably what I'll do then.

I always use muslin. Nobody will see it.

I try to use leftovers from the front of the quilt for the backing. If you have some leftover, I would try to do at least a border using it on backing so that the muslin does not show when the wallhanging is hung.

I use muslin a lot for this and it works very well :D:D:D

Yes, I used to use muslin all the time for backings.