To be fair it was tabs of acid rather than anything precisely measured, but it was enough to keep me going for 48 hours. Might have been more, might have been less, but that's really a bit too much.
100 mcg is to me a standard dose, and having done 1000+ mcg a couple times myself I can say that's a lot! I also had HPPD after a year or so of heavy psychedelic use.