Cascara is a great bow wood, but with every second string bow wood you give something up. Cascara because of it's flexiblity, and easy to work belly are at the top of my list as to bow woods I like.It is a easy to work wood with handtools, spokespaves work great....it is a bit like working yew. Here in the northwest, My first pick would be vinemaple (as Bryce as alluded too as well.) next would be pacific dogwood, Cascara , hazlenut, then yew....in that order. Cascara does not need to be backed, BUT I would burnish the back well, backing with silk works good......black silk against the salmon colored Cascara looks good, to my taste.
VMB