ETOPS
Not sure what kind of an aircraft your operating but you might review the Part 135 ETOPS requirements as most, if not all corporate aircraft will not be able to comply with Part 121 guidelines.
Basically 121 looks at the "critical fuel" scenario which for fuel purposes, and snaps shots the aircraft to 10,000 for the diversion. The APU is running and there are icing considerations applied. This scenario assumes that you had a engine loss combined with a decompression. Most if not all corporate aircraft in oceanic ops have supplemental oxygen which eliminates the 10,000 EO cruise alt, thus they continue to have the range to make a suitable alternate which they may not be able to do at 10,000.
Each operator applies for and receives ETOPS approval based upon any number of variables, so what might work at say Delta, might look a little different at BA, or UAL, etc. although there are basic requirments applied to all.
Sorry for the vague answer but it's hard to put a definitive signature to every operation.