Happy to help! Here's the r/microdosing wiki page on LSD - basically, the concern is that the drop of acid didn't land in the dead center of the square, so one corner might have a higher concentration than the others. If that happened and you just cut it in half, it's a gamble - maybe you get half, maybe you get a quarter, maybe you get two-thirds. Dissolving the whole thing in a known quantity of water will let you more precisely divide it up.