Thanks for the reply _mARCel_,
The reason I wanted to keep the GUI responsive is because after certain stages of processing I wanted to get manual user intervention, for example to clean up extra artifacts after aligning photos. I am glad to hear that someone else is using PhotoScan in the same way, would you be able to share your script? I imagine that the processing we are doing is probably different but the queuing stuff would be incredibly useful for me.
Regards