Major airport (KSAN by LatinVFR) upon setup, choosing a gate for a commercial airliner, the gates all show up in GSX Pro as "Ramps". Selecting Ramp 3, (I surmise it's gate 3) I am told it's 'too small for my aircraft', it is a commercial airline gate with a jetway, flying a 737-700, one of the smaller 73's... what gives??
Before reporting any problem with any 3rd party scenery, always indicate if it's an airport bought on the Marketplace, because if it is, GSX cannot read its airport data, because it's encrypted. However LatinVFR has unencrypted versions of their airports available for download, which you can place in the GSX profiles folder, so GSX can read data from there.
If your version is not encrypted, assuming GSX read the .BGL that came with the airport ( which you can check in the GSX parking customization page ), the parking spots there are taken from the airport file itself so, if the airport is naming a parking in a certain way and has set a specific radius, GSX will show just that.
Note that, in a recent update, GSX will display parking spots that have their name set as "NONE" ( that is not set to any "Parking" or any "Gate" ), instead of displaying "None" which might be confusing users, that spot is listed as a "Ramp", but that's just a visual thing in order not to show it as "None", which is what is inside the airport file. It won't change anything the way the parking works ( or not ).
About the radius, and the parking spots reported "too small" for your aircraft, again, GSX doesn't try to interpret things: as explained in the manual, it just reads the parking radius from the airport file, and compares it with the current airplane half Wingspan: if it's smaller, it will say so.
And of course, this can be customized as explained in the manual, and there's even an option in the Settings telling GSX to always ignore the parking radius.
Second problem: GSX never gets the passenger count correct, shows 174 or something, max on 737-700 with single class seating is 148. How can I fix that issue, please? Have updated flight plan with correct time in SimBrief prior to flying (KLAS to KSAN). Must I 'load' the passengers via GSX prior to takeoff or does it read the correct passenger count from SimBrief?
This has been discussed so many times, basically every day, last time just yesterday:
https://www.fsdreamteam.com/forum/index.php/topic,28022.0.html