"GRT" timed down and gone. 2 lives, 5 bombs total. Started said phase with 3 lives, 1 bomb.
Taking out that time from
"GRT", which lasts about 1 minute (a bit over I think), it leaves ~13 seconds in
"GRT" where I actually dodged without invulnerability (of course, I still tried to dodge with invulnerability for practice and such). Divide that down, and you get about 2 seconds in before I needed to bomb. Again.
Seems like those 6 seconds of victory were a complete fluke ;_;
Some analysis:

-The bullets move so fast, that not even Reimu's unfocus speed can outrun it;
this needs a Marisa check, though PC-98 Marisa doesn't seem to be fast like the current Marisa.
-Circles. Lots and lots of circles. Too bad not all of the bullets are 1x1 in dimensions like the snowballs.
-Fortunately, the bursts are close to each other (in terms of position), so it's like
almost like dodging a circle after another circle, etc.
Unlike Mokou's Rings of Death, which are a bit more spread out-Another close comparison to
"GRT" would be Mid-boss Orin Stage 4 Lunatic SA.
Going to research
"GRT" a bit more from my video file.
For some reason, researching this is fun.