Use mono of a similar diameter to your braid as backing, attach using a Albright , UNI to UNI , yuca tan etc. mono will also stop your braid slipping on the spool. Don't fill your spool right to the top leave a little shallow. If you have a spare spool use this in the following way. load on the braid first then attach backing , fill spool to desired level. you now have a perfect filled spool with the correct amount of backing. take that spool off and wind it back on the spool you require. Takes the ball ache out of guessing how much backing to put on.