I have done more than several large cooks now including multiple meats. Did a grad party for 300 a few weeks ago serving turkey breasts, pulled pork and baby backs. The only thing I did on site were the ribs. I did 100lbs of pork butts which translated into about 60 to 70lbs of sandwich meat. 50 lbs of turkey breasts and 40 extra meaty racks of pork loin back ribs.
I also did a full size hotel pan of dutch's beans. There were other salads etc. not provided by me. I did the pork 2 weeks in advance. Bagged and frozen until the day before the party. Did the turkey the night before. Sliced, bagged and refridgerated. Rewarmed both meats in roasting pans.
Did a wedding last weekend with pulled pork, double smoked ham and again dutch's beans. Again the pulled pork was done the week before and the ham was done on site.
So keep in mind you can do much of this before the party. But if your smoker will only hold 2 10lb butts cooking for a couple of hundred is going to be a lot of work just by repetition. I can do 100lbs plus of pork butt on my smoker at a time so it's large group cooking friendly.
I don't know if it's the pork butts I get here or the way I cook but I don't get the 50% shrinkage most talk about. I get somewhere around 30%. I usually wind up making more than is needed as pulled pork goes a long way. But one of my worst fears at a catering event is running out of meat. I figure 6 to 8 ounces of meat per sandwich.
I should mention I don't do this to make money. I do this because I love to do it. I do it for friends or friends of friends. I don't charge for my services directly but I accept tips and the party host pays all the grocery bills. So I'm pretty casual about it. I generally don't provide plates or cups napkins etc.
I have probably a dozen cooks now ranging from 100 to 300 people so I have a good idea of whats needed and when to start preparing. It's a good deal more work than most people realize. I'm to the point where I need commercial fridge and freezer. Been looking for something used for awhile now. Becoming a problem finding enough freezer and fridge space for cooks of this size.
In the end you made the right decision to stick with parties of 30 or so given the size of your smoker. It's easy to get in over your head the first couple times and you run the risk of frustrating yourself and never want to do it again.
So keep on smoking and maybe look into finding a larger smoker if you find you like the party cooking gig.