Chris,
Beautiful bow-- elegant simplicity at it's best.
How did you prep the IPE & hickory for the TB3 glue-up? I want to build one just like this (but around 50-52# @ 28"). I've got some nice IPE and a couple of hickory backings in the basement just calling my name.
I also want to make a couple of lightweight (28-30# @ 28", probably 66" nock-to-nock) ones like this for my daughters. Would a 1/16" hickory backing be enough? Reason I'm specifying 1/16" is I've got a thin slice left over from sawing some backings out of a hickory board. I could make a backing out of it that would be maybe 3/32 in the middle and 1/16" out past mid-limb to the tips.
Jim