IIRC the C4 MC don't have spin-up time because they are not rotary gunz like those C1-3.My recollection of the turreted or gimballed versions is that it was the 3s that had the worst spin up time 4s, which don’t seem to spin, weren’t too bad.
When using MC, I skip the C3s as they have the worst spin-up. The rest in the combo melt armors in no time~!.