Dear virtuali,
if you already change the approach of the tanker, you should look at the whole thing optically.
It makes no sense to leave the baggage loader in the standard position - distance to the plane - as the tanker often "drives through". an optical mess.
It also makes no sense to let the catering vehicles drive along with the tanker at the same time. On the one hand, the tanker has to take an unnatural path - bend off - on the approach, and on the other hand, the 2nd catering vehicle gets in the way when leaving.
I think your previous solutions were better, either the tanker or the catering vehicles, but not at the same time, but in a row.
You can of course argue that this would take too much time. But you can easily handle that.
The easiest way would be to set a specific process.
If the catering is requested, GSX2 only needs to allow a simultaneous boarding of the cabin crew. In order to do this, the time between boarding the cabin crew and boarding the passengers would have to be extended, just in case the catering request is made before the boarding. Additionally provided with the "if" function, allow
the boarding of the passengers only after completion of the catering and closing the right doors.
This would also make the separation of cabin crew boarding from the boarding of passengers superfluous.
In addition, an option "one-click service" would be nice. Refuel - catering and boarding, with a click triggered and processed step by step.