Ive used cumaru twice before, its a really pretty wood, and i was advised against using it, but hardheaded as i am, i went ahead. Just like everyone said, it was completely overpowered by my 1/16 hickory backing, i also tried a really straight grained piece as a self bow, it had good moisture content, but after tillering it to ~#40 @ 20, it blew on the tree. With how similar the specs seem to be to ipe, it truly doesn't compare.
My advice- If you have to pay for it, dont get it
- If its free, give it a shot, you might be able to make it work
PS:Ive used it as riser wood, and it comes out nice