A few things that come to mind:
Both pilots need to be type rated on your Lear.
Good planning is critical but can be a lot of fun. Start yesterday. Have you taken any sort of Int'l procedure training course? Even so a lot will have changed...it always does.
Contract with a handler..at least on your first trip.
Use the SAFA checklist to be sure you have all the docs a ramp check will expect you to have. PM me with your email if you need one.
Lots of great, and current, info about your Atl. crossing procedures on the N. Atlantic enroute chart 1/2.