What you could do, is lay down some standard "backing line" first, just enough to cover the bottom, then us either a nail know or
double uni, from backing to lead.
Use an Arbor Knot for reel.
Some will use a Uni.
You could also put down some electrical tape on the reel first, or right after attaching lead to reel using an Arbor knot, place the
electrical tape and then reel on line from there.