Half inch square is about right for your tips. You can make 'em smaller, but for a more rugged hunting bow, I would leave as is. Cut your grooves in teardrop shaped from back to belly. You could get by with as little as an 1/8" between the grooves but why would you want to. Be kinda flimsy IMO.
No, and can get by without tip overlays. Beef up the loops with extra B-50 or something.........Art