Daz, GSX should be able to run in both simulators without issue. That said, in order to use GSX Level 2, you must have base GSX installed and activated, so you would need base GSX in P3D if you're going to run GSX Level 2 anyway. As for GSX being run on multiple computers, I don't think that should be an issue as long as you own both computers. I haven't run into issues, anyway. Perhaps Umberto could better answer this. As for the B1900D, GSX should be able to refuel it, but I'm not sure if there's a GSX configuration file for it provided by FSDreamteam, if somebody created one and uploaded it on the forum, or if you need to create one yourself. Hope this helps.