1/2" of osage with a 1/8" hickory backing can make a 64", 70# bow, with no power lam, with a finished width of 1 1/8 - 1 1/4", with no threat of the handle popping off, in either a reflex or deflex/reflex profile. I wouldn't glue it up with the osage 3/4" thick, but that's just me.
What draw length?
I agree that Dean's dvd is a wonderful resource for these kinds of bows.
The key to a secure glue joint for adding wood to the handle lies in surface prep, glue choice, and gluing technique... and to a lesser degree, how it's tillered. Done well, the glue joint will hold just fine even if it bends some into the joint.