For all your hand tying needs for round rubber and silicone skirt material and accents colors for Jigs Spinnerbaits Buzz bait & Blade bait.
Go to Red Rock Threads
Coats & Clarks Upholstery thread 150 yard spools 135 mil.
It very strong thread and easy to work with.
With 20 colors to choose from.
All lures are tied with this thread.

How do you finish it off and do you use superglue or fingernail polish to hold the thread/knot?

I finish off tying with 3 half hitch knots . I never or have ever used glue or nail polish
Tying half hitch knots locks the thread inplace they wont slip or you cant rotate the skirts. There is no movement in the skirt material tying this way.