Welcome. I moved to Cornwall in 2016 and inherited 50 odd apple trees. We have had great fun with pressing our apples. Much smaller scale than you and I am amazed how much we pressed (200 litres of apple juice and 90 pints of (attempted cider) given how many windfalls we had.
Lessons I have learned (and I know I will have a lot more to come):
1. It takes a lot longer than you think to prune an apple tree so with 1,200 I suggest you start two years ago
2. Come pressing time I hope you have plenty of friends. Recruit as many as possible as you will need them to collect, crush and press the juice. I take it you will be using fancy modern machinery which will make it easier.
3. Cider - I don't have the knack but I am still going to try and damn well drink it even if its more like paint stripper at the moment lol
4. The left over apples that you didn't get round to juicing - look for a local coder manufacturer to buy the apples, Cornish Orchards near me will buy as many apples as anyone has I believe.
Good luck