Backing with anything but sinew is really only splinter protection. Silk, rawhide, canvas, burlap, fish or snake skins, all will help prevent splinter raises. The lighter weight hte backing, the better.
It is said that backing with raw flax -- NOT linen -- will improve performance to some degree, I have the flax and a bamboo straight self-bow that needs a boost in draw weight, and will be applying combed flax, and I intened to document the performance increase.