The Parking position doesn't have anything to do with the jetway alignment.
Or, more precisely, it doesn't if you use a GSX parking assistance (Marshaller or Docking System) AND you have customized the Stop Position. If you haven't customized the Stop Position, the default strategy of placing the airplane center of mass in the center of the parking will be used instead.
Should I align the jetway using the parking position or stop position?
The Stop Position, of course. The whole chapter is named that way, because it's the only thing that matters.
Also, is the stop position different for each aircraft? If so, how would I know that the stop position is going to work for the multitude of different types without testing each one?
As explained in the chapter I asked to read, the final goal is having the airplane PREFERRED EXIT to always end in the same position.
When you edit the Stop Position with an airplane, GSX will save it in the .INI file by taking into account the difference between the Preferred Exit and the Front Gear of the airplane you are using to customize the parking. This difference will be *subtracted* to the Lat/Lon coordinates that will written on the .INI file.
When you'll use the parking with a different airplane, the Stop Position in the .INI file will be calculated by taking into account the difference between the Preferred Exit and the Front Gear of the airplane you are using now. This difference will be *added* to the Lat/Lon coordinates found in the .INI file.
The result will be:
- The Front gear of the new airplane likely be in a different position on ground compared to the front gear of the airplane which was used to customize the parking, just like in real life.
- The Preferred Exit of the new airplane in the SAME position of the Preferred Exit of the airplane which was used to customize the parking.
So, we achieved the goal of having different airplane models having their Preferred Exit ending all in the same place. Which is precisely what you need to be reasonably sure that a jetway that worked while making the parking with an airplane, will also work with any airplane, with the exceptions of too short jetways that might not be able to reach a door because of its height, but these are less common and easier to solve (select a longer jetway).