So....how the hell do you even do the sisters on normal? Because even with the blessings it's damned impossible. Getting my shit rocked and starting to get really fucking annoyed.
Like, getting SS for them, or just passing?
What I did for SS was basically save scum. Don't try until the vending machines give increased perfect tolerance, and increased perfect progress (the one that lets perfects crit from the start can work too, but the increased tolerance is a must have). Pick glass as your free good mod. Reroll the blessings you get until you get more glass. I rerolled until the first run was all glass. Then play. Go for the first sister until it gets to the part where it's just quarter notes. Like, evenly spaced, no fuckery. Then switch to the sister that gives buffs, and keep going until you get the second glass from the first progress reward. Things just got a bit easier. Switch back until just before the first curse, then get the next buff, and repeat. Once you have four glass, it's basically impossible to lose. The hard part is just getting four glass without missing a perfect. After you manage it, just edge the sister that curses you until you have a blessing saved up. If you actually trigger the curse, you're pretty much fucked, so don't do that. I usually made sure I had two blessings whenever I went past a curse threshold, in case I forgot, fucked up, or progressed faster than I meant to. Swap between them enough that the curse one doesn't fail you, but not so much you get to the curse. Once it's hard to not get perfect for every note, throw some mods on to make your progress faster, and life easier. Needle is a good one, especially with the glass, when you're going for SS. If you never get a hit instead of a perfect, it's just free money; and if you stack glass enough, it's basically impossible to get a hit instead of a perfect. Crits are nice too, but they're a "sometimes" bonus instead of an "always" bonus, at least until you stack like seven. Oh, and there's a little number on the progress bar that shows how many blessings you have, it's a big help. If you miss a perfect, restart.
If you just want to pass, it's a lot easier. Don't go for glass, because it decreases the perfect zone if you miss. Don't go for needle either. It makes hits count less. In a non-SS run, that actually matters. Instead go for things that increase your progress, or the guardian? one. The one that has a chance for missed notes to not count. Stamina is also really great for both normal and SS, it means you have to swap less, and swapping is when you're most likely to fuck up. I think it was called Sap or something? The one that makes the bar drain faster, but hits and perfects are worth more? It's a trap on this level, don't pick that. When there's only one bar, it's pretty much only beneficial. But you have two bars, so you idle a lot, and the increased drain really fucks with you. If you've got one of those three traps; glass, needle, or sap, avoid them like the plague. Don't pick them, even if you have to reroll. It can take a few tries on the first slot, because there's only two options, but everywhere else should be good. You only really spend loads on rerolls for SS. That said, having cash to be able to reroll is definitely helpful. You might could try grinding some other girls till you've got loads of dosh to throw around.