Whole Pig

It sounds like you have a good plan.

60 lbs dressed weight will yield 20-30 lbs of meat (if you are good at pulling all the little scraps) - I usually figure 1/3 lb per person on average consumed - so that should cover your 55 ppl, especially if you have some sides and other stuff for them to munch on.

With a splayed pig that size, it might be less than 9 hours.  Just check your temps and when done, pull/slice the meat, wrap it and put it in a cooler wrapped in towels and it will be fine when you need it if done early.

I have done 80-100 lb pigs, non-splayed, in a home built box oven & manual rotissery and been done in 6 hours.  I have no thermometer - and at the start, I have the oven at a high heat to give it a good kick start (probably 400 degrees, then it gradually cools down - probably 300-ish for the rest of the cook.

The oil, salt & pepper on the outside may not do much for you - the skin is pretty thick - and you get plenty of rendered fat dripping out to help crispen up the skin.  It won't hurt.  It will be interesting to see if you can still taste any of it on the skin.  

Post plenty of pictures!  It will be delish!

You've gotten good advice . make our plans and have a great time.

The ones I've done were 60ish# and were done in about 7hrs.

Have fun and do send lots of -view.  .  .

We always did a low and slow and we learned that like butts they all cook a bit different. We started wrapping ours in chicken wire to help hold it together and not lose anything off the hog to the coals. Just a thought.