The more opinions you get the more confusion can
set in. Many of us have gone the lighter braid route
because we have confidence in it despite how thin
it may seem, 10# braid has a high breaking strength.
If you feel more comfortable with 20#, go for it. For
me, that's what I put on my casting reels.
We all have different experiences, plain and simple.
As for copolymer line like Yo-Zuri Hybrid, etc., they
are great lines, good for abrasion resistance, and
so on.
Some are coated or bonded with fluorocarbon.
Using fluoro as a leader is fine if you want to use it.
Has its own advantages and disadvantages.
I've taken advice from this forum and made purchases
based on it that I later regretted. My experience differed
from the other folks. You may drop some $$ on pure FC
and love it, or hate it. Part of the game as you develop
how YOU like to fish.