Do I have enough meat?

Ok, I'm getting worried that I didnt buy enough meat. I'm cooking for my church's summer picnic this wknd. I was told to cook for 60. So I bought 4 big butts: 38 lbs raw meat. I figure I get 60% yield so that gives me 22 lbs finished meat.

Now I'm told the number may go to 80. But I know that many of this number is kids and we're also cooking hot dogs.

Should I stop and buy one more small 7 lb butt? I always worry and cook too much. But I cant help worrying about running out.

I just got a confirmation on the head count. 60 adults, 20 kids. Assuming half the adults want a second sammy, and assuming all the kids just want hot dogs only makes me a little shy. This makes me nervous. I'll grab another butt on the way home.

Thanks!