Not really in the mood to grind TTF (boss RNG) since I got work to do, but here's a couple of things for people trying:
Getting Dubswitch as HU
Rather than dodge DRL if no invinc, get your HP to like 700-800 (easy with monomates and getting hit) and just tank the hits for DF. I healed too much in this video (shouldn't have used monomate).
This is Vol Opt 1 as HUcast. NS is the easiest way to do it, but it is possible to do NSS with very good timing (I suck, so I can't do it :D). My angle is bad on the second screen as well, but this is roughly how it works. Each extra screen you get with the special is an extra multiplier (i.e. 2 screens = 2x damage on core, 3 screens = 3x damage, 4 = 4x)
Edit: For Vol Opt, I think the fastest way to do Phase 1 would be to destroy the first set of screens, then angle yourself for 4x (stand near the centre) on the 3rd set of screens, but that is RNG...