Eh, if the elm can take the compression, and the hickory is good tension strong hickory, I say it is fine, and should make a great bow! I've made quite a few bows from staves with that much reflex, in different designs and weights. It really depends on the quality of the wood and the design/weight/draw length. In one circumstance, 4" reflex might be fine, in another one though, it might be a recipe for disaster. I mean, 4" is a lot of reflex as rule really, but I think you can pull it off. A good seasoned, good quality osage stave with that much reflex can be wicked, not wanting to give up any set. Those staves can be a trip to tiller! But with your specs and target weight, if the elm is good solid stuff, you should end up with a nice bow with around 2" reflex or so maybe. I haven't worked much elm, but if the bellywood was a softer wood like maple, you might end up with some set. But even so, I find when you glue in that much reflex, the backing typically will want to hold the bow into reflex, even if the belly wood is not that strong in compression. For example, I glued up a bamboo/purple heart/jatoba trilam elb recently. The jatoba ended up chrysalling horribly, before I could even string it I think. (Never using jatoba again for belly wood, never again) I was chasing hinge after hinge after hinge trying to tiller this bow. But, because I glued in darn near 2 1/2" reflex, the bow still held almost all 2 1/2" of it. Reflexed bamboo bows are good for that I find. It's best to tiller these carefully though, making sure you longsting tiller is good to go and bracing it higher than normal for first brace, preferably full brace, as long as you are sure you nailed the longstring tiller as much as you dare without whipping the tips. Reason being, is that they can want to flip on you at a low brace.
