I heard someone say a long time ago, they wouldn't ride in a group larger than four, and I've found that every time I've ridden in a group of more than four it always turned out to be more work than it is fun. Just too many different riding styles, the slowest are too slow for the group or the fastest are too fast, so four is rule with me now.
Had a nice ride Saturday with three other friends, and it turned out great. The fast guy lead the way, with second fastest to follow, and me in third, while the least seasoned rider stayed at a pace he was comfortable with, but not too slow. No waiting for anybody, but not too close to each other.
I one section of interstate on our way to the back roads, we were in a well spaced group, yet some idiot cager felt it was necessary to force her way in between us, like so many other times I found "Safety in Numbers" doesn't work on brain dead idiots.
As for large rides like a charity event, I rode in one with approx. 200 bikes, and that was enough. Too slow, and too many bikes bunched up, it sucked. I was stuck behind some clown that wobbled all over the place, and put his foot down in turns, he wasn't alone, there several posers doing the same stupid crap because they couldn't ride. The longest 100 miles I've ever ridden.
A few years back, there was a charity ride (I was not in) and a teenager in a car crossed the center line, and mowed down several bikes, killing three riders. I don't believe "Safety in Numbers" works with motorcycles.