Although it's another two splices to cut it's much, much easier to find perfect wood for a 5 piece core. Handle, 2 bending limb pieces and then two for the tips.
What draw weight are you after? And draw length?
Get your core made first then work down the horn.
Do you know about the core basically working as a form when it comes to gluing the horn?
With that in mind I'd want the grip 1 inch thick, the bending limbs around 3/4 and the tip sections the same. Also you want to be cutting the parts a good 1/4 - 5/16ths over width (apart from the base of the tip section wants to be finished dimension). Cut the limb splices first, glue up then cut tip splices. Re-establishing a true centerline inbetween.
