Sure a lot of different thoughts on how we do things. Whatever works for a person is best for him I guess. Me? I'd cut the loop off and since backing is some sort of braid that draws up nicely I put the backing to fly line with a simpler Uni-Knot. Simply make a big loop with the backing, run the tag end through the loop about 8 times, snug up and move close to end of fly line and cinch down hard. Makes a nice tight barrel on the line that looks similar to a nail knot tho it is slight different in construction.

Since I generally use furled leaders now I do use the front loop for the furled leader. If I do use an all mono leader I then cut loop off and go with a heavy base mono and a nail knot to run leader off. Actually, I use a snell knot to put the mono to fly line. It is EXACTLY the same thing as a nail knot but much faster to tie.