Yep... The typical yield for a Butt is 50-60% of what you start with. There is moisture lost during cooking, Fat melts away or is later trimmed, Sinue removed, Bone, Etc. So if you take the weight of Pulled Pork you want and divide by .5 you get the amount to Purchase, weight of Raw Butts. Many go by 60% yield for family, but in Catering, you want a little wiggle room...Cousin Danny RSVP's ONE, then shows up with his new Girlfriend! Uncle Fred only eats Meat and eats 6 portions rather than the 2 you planned for. So by figuring a 50% yield (/ .5) you end up with 10% more but everyone is Full and Grandma get's some to take home, so she don't have to cook a couple days the following week.
As far as Sliced Meat, Double Smoked Ham holds well and is really easy...Buy some Boneless Hams, 4-5oz per guest with a 90% yield. Smoke them, slice and pan, shingled slices, with Pineapple Juice, Brn Sugar, a bit of Mustard and a little Ground Clove. The pans of Ham can be reheated and hold up well. If you want a different meat than Pork, Smoked Brisket, 4oz portions with a 60% yield, is also good. Smoke to an IT of 185F-190°F, not quite perfectly tender, slice and pan with Jus. The Panned Brisket can be reheated in the Jus to a min of 165°F, where it will finish getting tender. It can then be held, over 140°F and served Au Jus or with BBQ Sauce...
...I know you TEXAS BOYS are cringing!
Any other info I can help with, shoot me a PM as I missed your question until now...JJ