I had an amusing if not you Stag Hunt experience as a best man, I was on the ground and got surrounded and peppered by my party and a group of very trigger happy school kids and had no marks. I suggest you mock the MTFU comments and get layered up.
IMHO vital kit is
As mentioned above couple of buffs around neck and gloves, I wore windsurf ones. Strong over ankle boots, turtle neck long sleave T shirt.
I then had Joggy bottoms under jeans (worked well), thick builders shirt topped with woolly jumper your Nan might knit. All under the provided overalls. You want to aim trap as much air as possible. (take water, you will need it wearing this!)
Best man had T shirt and jeans, he looked like a bad case of chicken pox at the end. Also – be aggressive and use smoke well, most people are terrible shots. It is a bit like Clarkson with AK47 on full auto in front of a van, lots of noise but actually very few accurate shots.