Fair enough, Nano, maybe you and Psilo bathe in the stuff. Erowid classifies 160-400ug as a "strong" dose.
I have no knowledge of the current LSD scene (other than what I read here), but historically blotter was typically less than 100ug, an average of 50ug has been suggested:
http://www.erowid.org/chemicals/lsd/lsd_article1.shtml
That corresponds with my experience back in the 1980s, and with most of the current reports I read on this thread.
Bluelight is a harm reduction site, and I personally find it irresponsible for blotter to be laid at 300ug when people are accustomed to, say, 50ug. I've been surprised by occasional strong blotter back in the day and fortunately handled it OK, but I know people who were not so lucky. LSD is not a toy.
I won't speculate on how you seem to know the dosage of what's going around. OTOH, it's good to know that the purity is improving (if it is), as I'm firmly in the "purity matters" camp. I would go for purity over quantity any time.
Finally, if you are surprised that Psilo gets visuals off less than 1000ug, then maybe you should suggest to him that he cuts down a little. Really.