tambourine-man
Bluelight Crew
I would also add that if you do decide on mescaline, make sure you have a day of activity planned (set and setting). For a first-timer, the prospect of a 8 or 10 hour duration can be daunting. Having something planned can help to alleviate that feeling of "chemical commitment". Perhaps a trip to a gallery or other visual stimulus? A walk through a park?
Whatever will feel best. Again, good luck.
Whatever will feel best. Again, good luck.