Sure, I can edit every single individual parking spot at every single airport I might possibly fly into with the -8. But I'm not a masochist.
The MULTIPLE SELECTION here, is your friend. No, you don't have to edit every single parking individually, it's enough to click the whole airport on the editor, which will select ALL parking at once, and set a Max Marshaller distance which works right for that airplane.
"Max" means max so, setting that distance won't change anything for other aircraft types, it will still be calculated automatically based on the eyepoint, but it will be UP TO that "Max" value, never greater.
Here's a screenshot of two FSDT products -- KLAX and GSX -- working together marvelously to make sure that I can't see the marshaller: https://imgur.com/HGThukr
You managed to find one of the very few parking spots we didn't set the Marhaller position manually. Fixed by running the FSDT Live Update now. Just be sure you remove your own customization, because your custom customization in %APPDATA%\Virtuali\GSX will take precedence over the one we made in the KLAX\scenery folder.