In using the the loop-to-loop with a braided mono double catch loop on the fly line- Why can't you splice a loop into the 30 lb. dacron backing. I have never had
a spliced backing loop fail w/ ~ 8 in. "spliced" inside the core. This gives you the smallest profile connection. If others have had problems w/ a spliced loop in their backing I'd be interested to hear about it as it might make me change my thinking.