Never mind the consensus. Unless you're a hardhead at heart, take it easy. There's no need to rush in to what most first-timers would consider a strong trip. 100ug will most likely be light but not too light, and a comfortable, euphoric, fantastic introduction to LSD. The ones telling you to take 2 are not erring on the side of caution, they're just going off their own much higher standards of a proper trip, and this is a harm reduction site. My first time I did half a tab, and it was absolutely brilliant.
EDIT: tell you what, why don't you take one, and if you're feeling like it's not enough by the time you reach the peak (+1 or +2 hours depending on your reaction) then take another half, or even a full tab. Just be aware that taking the extra full tab will take the trip to a totally different level, and you won't be able to gauge what it'll be like from the one tab.