Hi-vis line…whichever you can personally see best in low light. Right now with the river being very clear a florocarbon leader on the end of either mono or hardline I agree is a good idea.
For fishing jigs in water less than 15′ mono or hardline. Mono for pitching jigs to shallow current I prefer 6 or 8#, deeper than 15′ I’d rather have hardline with a 2-4lb diameter for no stretch and better feel. I don’t do well with blades on mono at all.
Easier for me tie to floro leader with cold hands than hardline too.
Lot’s of good options mono or hardline and if you have spare spools for your reels you can be more versatile by being able to swap from mono to hardline in short order. Then you can test which works best for you from one situation to the next.
Brian