Darling, I am no expert, but I don't think there's any easy way to do this. You could try gradually adjusting the schedule before you go. Or you could gradually adjust his schedule when you get there. But either way it means lots of missed sleep for you. So, you could just go cold turkey once you get there, and it may all come out the same. Although, I have to think that if you've already tweaked his schedule by a couple of hours before you go, that you'll have a much easier transistion time. You'll only have to change things by a couple of hours once you get there.
Oh, and don't worry about making milk, when you make it, your boobs adjusting, etc. You'll just be making much ado about nothing. As he adjusts his schedule, whichever way you choose to do it, your boobs will adjust. I mean it. It sounds like your a little overwrought about that part of it.
So, maybe start adjusting by an hour a week. Start doing first morning awake and last bedtime at 8am and 8pm. Then the next week adjust another hour 9am and 9pm. Maybe you'll need 10 days for each adjustment.
Jet lag tips: drink lots of water while traveling and put yourself on the local schedule as fast as you possibly can.
Honestly, I think at 7 mo your lo will adjust better than at 3 mo.
