Hickory is a poor choice for belly wood. It tends to fret easily under compression. My brother makes some nice bamboo backed Iron wood (hophornbeam) We've also had decent luck with good hard maple. Been wanting to experiment with Elm but haven't got around to it yet.
I woulda thought that hickory would work, but I'll trust ya on that.
Iwas just given a 5" dia. log of hornbeam last week by the landowner of the parcel I hunt. I told him, I'd build him a bow as appreciation for that privelege, so maybe boo backed hornbeam then...also, I'm supposed to be getting some elm logs from the parks dept. in town. I may try elm too.
I'm afraid that IPE, YEW and OSAGE are unheard of around here....I'd have to ship it in, so I think they're out for me.