Let's get this stupid story about red/blue lines finish for good:
If u are great player, HU in general you must win most pots, and given that in HU no1 hits vast majority of the time, and even when they hit, you can take them off those hands, and the better you are, the more and bigger and more often you will take away, and they adjust incorrectly and try to take a stand and pay you off, or try to bluff and get owned with you snapping them off.
I've thought it's impossible to fight fire with fire with uncaring maniacs, but i was so wrong until Ive got better understanding of the game and more confident, and when i play a maniac most times what happens is i start playing with more fire, either he lucks out 2-3 times and donks it all backanyway, or busts quick and leaves or reloads, busts and leaves, or he turns into almost a NIT.
BOTTOM LINE: If you can't have positive redline in HU - you are not great player. Yah, you are ok on small-midstakes to crush donks, regpish, but not good thinking somewhat advanced player. Ofc there great players who are consistent big winners with blue-line and redline around zero or negative, but with that style of play you can not increase your winrate to skyrocket, cos this style of play HAVE TO include lots of trapping, and since no1 ever has anything in HU -it's super tough job.
CLIFFS: If your NSD suffers in HU - your aint rock star
But part of those who DO show redline here is FAKE anyway, their redline is bigger then it would be if they played better.