From my own experiences, I've found it's very hard to overdose on smoked/vaped harmalas (I only tried freebase so far), I've vaped big chunks of freebase (didn't weight, estimating up to 300mg) resulting in the same effects of 100mg doses. I don't know why, but once you're stoned on harmalas, you can't go further no matter how much more you smoke (Caution: I don't mean gigantic +gram doses!)