20lb not to heavy for mono on TSS4. I don't think the TSS4 is good for much less. Plenty of thinner diameter mono lines to choose from. Go for them. If price is an issue save some bucks by only laying on 150yds with some heavier cheaper backing. A few good sessions will flog the mono and best to spool up with some fresh stuff. I go straight to slug. I use a black swivel on front of slug. If you get line twist, on your way home or to the next spot, tow your line behind the boat with nothing attached. I don't see the point in making it any more difficult for yourself. When the spotties are on you wanna be into em and not dick around with a set up that will only slow you down.
Single hooks are good. 2/0 could be a bit small.
I haven't trolled live baits for bay macks yet. This year I am definitely going to give it a go. Last year I got a couple of nice spotties that inhaled grinners that I was pulling in. Phils rig would do the trick. Down facing single or treble in the ass with an up facing hook through the snout would do the job fine i reckon. Was Phil using single strand or crimping coated multi strand? Crimping coated multi strand would be fast to set up by having the front hook rigged leaving a tail of wire to size to your bait. Crimp n snip then ready to go.