In my experience LSD has never increased my level of fluency, though mushrooms and MDMA do. Have you tried MDMA? It seems to be pretty consistent in making speech completely fluent/effortless for people who stutter. If you haven't tried it I would highly recommend it. Your level of fluency will return to baseline once the effects wear off, but wow is it an incredible experience to feel so unconstrained by your speech while you're rolling. I'm a regular user of cannabis as well and have consistently experienced a benefit to my speech when I use low amounts of it that is high in THC, and when I say low amounts I mean like 1-3 hits from a smoking device or 1-3 draws from a vaporizer. I would like to try cannabis high in CBD to see how that affects my fluency but I don't live in a legal medical or recreational state. You can buy CBD products legally online that are derived from hemp but these have less than 0.3% THC in them and I'm looking for something more along the lines of a 1:1 ratio of CBD and THC to get the whole plant 'entourage' effect. Anyway, I'm glad that you've experience some benefit it sounds like and spoke up about it in this sub!