I really relate to this. My ex-wife is pagan and they lay hands on things more than Pentecostals. I've done a lot of theater, too, and people have been angry with me for refusing hugs or stepping out of touching circles. Teaching, too-- I remember one morning meeting I was at where we were discussing inappropriate ways to touch students. I was sitting between the policeman who was speaking to us and a teacher who liked to touch kids. They both kept using me to demonstrate ways of touching that were friendly but might be considered inappropriate. They were both nice and funny about it, and the policeman was even cute, but I was jumping out of my skin and useless for the rest of the day. I could not vocalize then how much it bothered me. I would be able to now, but I wouldn't be able to be nice about it.
I think, though, that pagans and theater people tend to be pretty tolerant of difference, especially if I can laugh at myself a little when I tell them, "I'm sorry, and I know that you mean it well, but it's upsetting for me when people touch me unless I know them very well." I hope I'll be able to do that next it happens to me. In theory-- it's great advice. I haven't followed it very often myself. It's embarrassing, and now that I am aware enough of my autism that I understand how important it is that I follow it, I hate being around people so much that I am rarely around people I do not know well.
Touching is such an important sign of friendliness that I think it's important to give overt signs of friendship that we are comfortable with. I don't mind smiling at people, but I have to make an effort to remember that I should. I do make an effort to adopt non-defensive postures (just not crossing my arms across my chest apparently makes me half as scary). If I were doing pagan stuff now, I would try wearing mittens for handholding stuff or even carrying ribbons for people to hold if mittens were too much. I would feel goofy and pretentious, but then I would look around and ask is I were really being any more goofy or pretentious than anyone else there. Think of the things they wear on their heads.
It might also help to think of ways to communicate this about yourself that would be in keeping with the conventions of the community. It would certainly be appropriate for you to talk to ritual organizers about accommodations you might request or make for yourself that would honor both your respect for others and your own particiaption. If you are asked to do any sort of initiation ritual, I would discuss making your issues about touch a part of it, both as a way of communicating them and as a way to make sure you are bound to the community in ways that are appropriate for you.