Sorry about not being useful. It was one about needing to update Coatl. But I had just done the update like three weeks ago when I saw a message in-game that said it would be "automatically" updated (I remember other updates were manual, no?).
At any rate, I downloaded coatl again last weekend and reinstalled it. I guess I did it AFTER my last CS 707 flight (where GSX did not work), and it works fine now. Marvelous! Now, I will check out the F1 MD-80.
OK, Coolsky Super MD-80 Pro does not have any method to open the cargo door or the right front service door.... that is not FSDT's issue, and your AI guys load right through them.... so, at least, I am not getting the tone repeating to open them.
Cheers!