As the title says, please modify GSX to remove the tug/towbar/pin while waiting for the two good starts confirmation.
In real life we always time our engine starts to be completed by the time everything is removed so that all that is left to do is to give the Ramp Agent the "thanks, two good starts, see you left/right/on-the-moon".
With the current way GSX handles it a lot of time is lost with the engines running, wasting fuel and time.
The engine start confirmation should be the last thing before saying goodbye and changing to hand signals.
That'd make the process a lot more efficient. Especially since GSX already takes quite long for the whole process after the parking brake is set, even before you introduced the new confirmation.