If the stave is clean and with a working handle, you'll get 40# @ 28" out of it. I'm partial to round bellies, but the only trouble with them on staves "that" skinny is that the depth might match or need to exceed the width for the weight you want, which makes for a bow that is as apt to bend side-side as it is back to belly. I'd proceed cautiously with a thick flat belly and gentle facets. Once you get it strung, round the facets over as you can to drop weight. I have a feeling you'll end up in the middle with a squarish ELB.