I'd say 2" at the fades and out 10" to half the limb then a straight taper to 1/2" at the tips(tips can be narrowed later to 3/8"). If your grain is somewhat iffy, I'd back the bow. Brown grocery bag paper is a good, strong backing that will help keep splinters down. You can also use silk(old neck ties or scarves from thrift stores or linen also from thrift store blouses, etc. You can use Tite Bond glue for these backings.