|When i get a reel where my spool of braid ( say in yhis case, your typical 300 yd spool of 50 lb. ) will fill. The reel up well below the lip of the reel ( i like my braid right up to the lip to maximize casting distance, but i use a lot of lures)...ill put on the braid right to the spool, wind it up as tight as i can so its as compressed asmit can be...then splice on some. 30 or 40 lb quality mono just to fill the gap. Then i know exctly how much mono backing will fill the spool with the braid coming up to the lip. Do this on the extra spool. Then pop off that spool, take the aluminum main spool, put it on, and tie your mono on directly to the spool. Wind it on tight and when you're done, that 300 yds of braid will have a mono buffer which acts like an arbor filler and lets you tie directly to the spool. You will have the mono going on under the braid...this works for me....as I rarely even get to the mono. Unless you have a big filler spool...than just go all braid...with some tape.
Let em go and let em grow