I've been making mine 4" and lengthening the handle a to hide the splice under the grip. If I can get away with 3" though, I'm going to do it! I have some shorter billets I want to maximise working limb length on. I go the extra mile too, and bind the splice with linen twine, then coat the binding with gelatin glue. Talk about paranoid. I'm going to do 3 Inches from now on. I have a set freshly chased, my shortest bow yet. Billets at 29", making for a 54" bow with a 4" splice. Now a 55" bow with a 3" splice. Just waiting on a new band for my saw to arrive........
Good question well asked Sleek!