Well it's not just GSX, I've tried some FSDT sceneries in P3D2 and all I can see are aircraft and jetways, so I hope something can be done. I have confidence.

The AddonManager installer moved my airports to its own folder and updated my FSX scenery.cfg, but didn't update my P3D scenery.cfg file. I fixed that in a few seconds with some Find and Replace though.
I've zipped a log file for the Couatl problem with GSX, along with a log for my attempt to launch at CYVR. This -GSX log mentions an error creating 'FSDT_Traffic_Cone1', but I've seen references to 'FSDT_Traffic_Cone3' too.
I've checked the new SimObjects folder and there are three models of FSDT_Traffic_Cone present.
My Prepar3D.CFG has two entries pointing to the new Simobjects\Misc folder. Are these correct and are both needed?
SimObjectPaths.6=C:\Program Files (x86)\Addon Manager\Simobjects\Misc
SimObjectPaths.1=C:\Program Files (x86)\Addon Manager\Simobjects\Misc
Regards,