I usually wrap over the starting tag end for around 3". Probably overkill, but I've always done it to try and ensure it won't slip.
If I did this on the top-end, it could reach the point where the arrow is nocked, which could make the fit too tight.
I lap over the finishing tag end 24 wraps and pull it through. Can't go much more than that--it will break if you do. Can't go that much with nylon serving, or a serving that has a sheath over a core--one of the reasons I prefer BCY's Halo, 62XS, and Powergrip. They are strong enough and tough enough to handle it.