As discussed many times on the forum, the parking type it's just a label, it doesn't have any relationship to the size, so we flag all as Ramp GA, in order to get rid of default ground vehicles, which will interfere both with static details placed on the apron, and with GSX vehicles.
This is a technique used by many other developers but, in our sceneries, we can use a custom GSX menu with more realistic descriptions, and in the latest GSX version, you can even see how many parkings for each terminal are usable for your airplane, which means it will be much easier and better than using the standard World Go-To Airport.
So, use the standard Goto menu only to position at the airport (maybe on the runway), then use the GSX menu with the "Warp Me here" option, which will just move your plane there, without activating GSX, basically replacing the standard menu to select a parking spot.
The latest version of KIAH use SODE jetways, and they are integrated in the GSX menu, using the "Operate Jetways" menu. They surely work.