Re: knot help
To attach your mono backing to the leadcore, use a Uni-to-Uni knot.
At the business end of the leadcore, I use a small Spro ball bearing swivel between the Leadcore and the leader. A good ball bearing swivel is a MUST with tube & worm rigs, as they tend to spin and will twist your line up if you don't have a good swivel inline. These swivels are also small enough to reel through the guides if you need too at the end of the day.
I remove a small section of lead from the end of the leadcore line and use a Uni knot to tie it to the swivel. Then I'll attach about 4 feet of 50# Flouro leader to the other side of the swivel.
I'm sure others may do things a little differently, but this has worked well for me.