If it is hickory you want, Pat has told you straight, both suppliers will give you a premium piece of hickory. There are some **** sources but you really take your chances on getting a good piece of hickory. The grain on your backing strip needs to be perfect otherwise you might as well go with something else or nothing at all. Boo is a good backing material for some core woods.
What are you using as your board material?
Linen and silk are good backings for oak and maple medium weight board bows and it is cheap. 10 bucks will buy you enough backing from a fabric store to back 20 bows. I have a 58# silk backed board bow that was one of the first I made that is still perfect, I get it out every now and then to shoot just because and I bet it has shot well into the 5 figures of arrows.