Is a sitter necessary?
Well, depends. With a low dose of admixture, probably not, unless you have some health issues that you are worried about.
With a high dose (which I don't recommend), it can be helpful to have someone not in the same room, but within earshot, in case you freak out and absolutely can't handle it, or something like that.
What about a shaman?
Shamans are obviously a mixed bag, but if you did find a shaman that had a great reputation, then would it be worth traveling to do a ceremony with them? Depends on whether you are going for emotional healing or insight/liberation. Shamans and traditional societies in general don't have any understanding of No self, so they can't help you in that regard. But they do have a lot of experience with emotional healing, so if you don't find much benefit doing it solo, then try with a good shaman. It may be worth it.
Well, depends. With a low dose of admixture, probably not, unless you have some health issues that you are worried about.
With a high dose (which I don't recommend), it can be helpful to have someone not in the same room, but within earshot, in case you freak out and absolutely can't handle it, or something like that.
What about a shaman?
Shamans are obviously a mixed bag, but if you did find a shaman that had a great reputation, then would it be worth traveling to do a ceremony with them? Depends on whether you are going for emotional healing or insight/liberation. Shamans and traditional societies in general don't have any understanding of No self, so they can't help you in that regard. But they do have a lot of experience with emotional healing, so if you don't find much benefit doing it solo, then try with a good shaman. It may be worth it.