Ideal lead core lb for salmon trolling

On our charter we use 27# Suffix Performance leadcore with Suffix 832 Advance Superline 50# as backer.  The leader is 30ft of 20# Advance Fluorocarbon.

We use the Sams Pro release on our boards so the braid makes it much easier to trip the boards once they get further from the boat. 
?

Mono takes up a lot of space on a reel compared to PP so you need to have a much larger reel if the backing is all mono. I splice in a section on  mom to put the boards on then the rest is PP.

I know some guys use power pro or other braid as backing.  I wonder why not use a spool of cheap mono for backing vs a $15.00 or more 300 yd spool of braid??

I believe that's the Willis knot James

I went with 18# because the lead wire was the same size as in the higher poundage lines and sank better. Flouro leader is 15 #. Haven't tried the newer thin ones yet because the old stuff still works. What's the name of the knot where you pinch off some of the lead  inside the core and slip mono inside the sleave sliding an overhand knot down to cinch it up?

Exactly the same as mentioned

I use 27# Tuf-line micro lead. Less drag than the regular or a heavier pound test. I use a 20# leader figuring if I were to get snagged or a fish did manage to break off that the leader would give before the lead.