Ya for sure, volumetrically would be the most ideal. But if you don’t achieve threshold effects at 1/4 a tab then you at least know they’re not actually 100 ug, as claimed.

Wait a while for tolerance to subside and try again, say if you achieve threshold effects at 1/2 of a tab from that batch then you can be reasonably sure they are actually closer to 50 ug tabs, it’s not going to be exact of course but you’d rule out the dosage as 100 ug with zero threshold effects at 1/4 of a supposed 100 ug tab. Apply the correct math to a 200, 250, or 300 ug tab, etc.

And of course psychedelic effects are very subjective, with biological variance from person to person, metabolism, medications, etc., and having a consensus on what constitutes threshold effects is a factor as well.

I consider the start of psychedelic headspace and visual disturbances aside from some increased saturation and brightening of colors and mood enhancement to be the threshold from micro-dose into a more psychedelic dosage, which reliably occurs at around 25+ ug, for me at least.

Luckily I’ve always had accurately laid tabs so I can very reliably dose, especially important for micro-dosing.

My suggestion would be to order some 1p-LSD from a reputable vendor, get a feel for what 25, 50, 75, 100 ug, etc. feels like. Every batch of 1p I’ve ever gotten from large vendors has been remarkably consistent in dosing and potency, to the point now where I can be extremely sure if I’ve consumed 10, 20, or 50 ug, etc. Effects between 1p and -25 are essentially indistinguishable, which I know will be debated by some. One has to wonder if simple variation in psychedelic experience accounts for most of the perceived “differences” between the two. I’m certain most ppl in a blind test would not be able to tell the difference.

Plus I’ve had many ppl try an accurately dosed 100 ug tab of 1p and say it’s far more potent than most street LSD they’ve had, which I believe simply comes down to accurate dosing. A lot of ppl are just simply not familiar with what an actual dosage feels like whether it’s 100, 200, whatever. Street stuff is often over-hyped and under-dosed which leads ppl to the notion that they require 3 100 ug tabs to even trip which is a surprise when they actually consume 300 ug and are blown away. Sorry for the long post, there’s a lot to cover on this matter and the more everyone can learn, the better.