To be honest I have never reheated that much at one time in one portion. What I typically do with left overs and an intentional additional butt, is pull it and then divide everything into family sized meal porportions. I use Zip Lock and other types of plastic freezer containers from like 1/2 pint to quart sized. I keep a day or two worth in the fridge and the rest in the freezer. The microwave safe containers get nuked, the non-microwave save containers get dumped into a glass casserol and nuked. Sometimes I might add a tablespoon of water to it before nuking, I don't know that it is needed, I don't stir while it is cooking, but it probabally would be a good idea (microwave cooking is another whole subject). A seal-a-meal with boil-in bags would be great, maybe Xmas?
Meanwhile, back on the ranch......
17 pounds! Now we need to know if you want atleast one whole butt for presentation to your guest if it is a party that you are a 'havin. I would assume that you do, just for bragging rights! What good is all of your work and know how if you can't show it off? The ooooohs and aaahs are an important part for ones ego.
Reheat that one wrapped in foil with some extra juice in the oven or in the smoker maybe 350 until it gets up to temp, and then give it maybe 30 minutes unwraped in the oven/smoker to dry up the bark if you like. Foil and re-rest. Plop it down into the middle of the prepulled meat and yell "Come and get it!"
Another advantage to cooking a day ahead of time is that cold meat will slice alot better, so if you plan on slicing any, stop cooking that butt earlier (180-85 ish), rest, fridge overnight, slice, wrap, reheat, and then serve.
Even if you are throwing a party, I would guess that reheating in smaller portions might be a better way. I am assuming that they would reheat faster and you could control the quanity better (no sense rehating food for twenty if only five showed up.
PS (like I haven't rambled on enough)
Pulling (Assuming that you are going too)
I caught something the other day about butts turning to "mush". Ain't no doubt that they will get very tender when foiled. I have had them so tender that it wasn't really pulling it as much as stirring it (Almost to a pate'). This would be a no no (The stirring that is) Don't overwork the meat as you pull it, I have found that it is best for me to pull off a chunk and work it down to a medium coarse pull or shred using tongs in one hand and a fork in the other. Trying to work with too much meat at one time seems to lead to some of the meat getting pulled twice or getting over shredded. Leave it coarse, it will continue to get finer with every handling and in general the meat is so tender that biteing through a bigger peice is not all that hard to do.
