ReimuB's autocollect thingy is pretty handy if you aren't too good at grazing/safely poc'ing, and MarisaC's bomb certainly helps if you don't know when you need to bomb. However they do pay a considerable price for the extra bit of security with their lower damage.
Ultimately, you're going to need to learn how to graze/poc safely/deathbomb anyway, and unfortunately without practice you won't improve at those aspects.
I'm kind of speaking from experience too, my first two 1ccs of SA were with ReimuB & MarisaC. I had to switch to a better shot type when it became apparent that the aforementioned two just weren't cutting it for Extra - and when I was trying to 1cc with ReimuA I was forced to learn all the other stuff I should really have been getting up to speed with from the start.
ReimuB's bomb can be handy at times for particularly dense areas of bullets, but it generally takes prior knowledge/planning to take full advantage of (example: S5 midboss Orin's first 2 patterns.
Replay just for the hell of it, don't try this on a real attempt unless you really want to be stuck with 2 power for Cat Walk. Have fun watching me try to remember how most of this stage goes as I haven't played it in months).
tl;dr: Your best bet would probably be switching to ReimuA now rather than later.
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On topic: Yeah, downward spirals are quite a pain. I sometimes find that just leaving it and coming back a little later, even if it's only 30-45 minutes, can sometimes break the cycle of doom. Other days just don't get better no matter what I do.
