Try hammering the wire before wrapping it to square it offa little.
You could also try Half Round Wire or after you wrap, use a rawhide
or delrin hammer and gently hammer the wraps so they flatten a
little, be careful not to hammer too hard or you will weaken the
wrap. If you doit gently you can get a nice flat surface on the wraps
which will shine nicely and it will hold onto the wire as well.