Dedicate thought to what you will do if you have an engine failure. What altitude could you maintain? What route will you fly? Compute equal time points and know when you are past them. With an big emergency (engine loss, depressurization, etc.) you need to have the "where am I going to go?" part already planned. Don't forget to update weather for your enroute alternates. The Jepps Atlantic high chart has a wealth of info on the info panels. Read them carefully. If the airplane is not certified you won't be allowed in RVSM airspace, so you'll be restricted to lower altitudes. I assume you have an HF radio???? Know the distress freqs for that also. Plan carefully and have an uneventful flight!