Sounds good. I do have a few small notes/tips:
- 3 1/2" of reflex is a lot. I would settle for a bit less. Maybe clamp in 3 1/2" so it will spring back a little, ending up with maybe 2 1/2"
- I'm not sure if hickory on the belly is the way to go. Maybe, just maybe, a maple belly may be better. Anyone else has a suggestion? Hickory-maple-hickory or hickory-maple-maple?
- A block for a handle like you describe can easily pop off. You could avoid this by gluing in a 'powerlam' between the backing and the core. This is a short (about 16" or so) lam of max. 1/8" in the center that beefs up the handle. This shifts the bend away from the fades, more towards the mid limbs, so the 10" handle block is less likely to pop off.
- A backing of 1/8" is great. It can be tapered a little, but is not needed IMO. Instead, I think it's better to taper the core. 3/16" at the center, tapered to 1/8" at the tips is perfect. The taper makes sure you'll not end up with only backing and core at the tips. With this taper, you'll also have sufficient thickness at the tips to include enough belly wood.
Good luck and post pics!