Using darktable drawn masks in gimp

I’ve spent some time drawing a mask in DT and would like to use that mask in GIMP. I’m asking if the plan I have make sense and how can it be simplified.

  1. Draw my mask and use it normally in DT to prep the image.
  2. realize that some operation would be better/easier in GIMP, like cloning a part of the image to take out a poorly placed tree, or make the area outside the mask transparent so I can use it for compositing it later.

so
3) duplicate the image to make a second version
4) play with exposure and mask to create a pure b/w image

now the part that bugs me
It seems that I can only “export” the image to get a real PNG that I can bring into GIMP to use as a mask.

The issue I have is that I’ve got the export directory pattern all nicely set up for normal pictures but I want this one the go into a different folder or have a different name, like imagename-mask-1.png

“selected image/Copy” does sort-of what I want but it only copies the xmp.
If I were to use export, i would have to play with the filename pattern each time.

I think I need a “selected image/save as” that actually copies the finished image or “export as selected” that looks like the export selected module.

or maybe there is a cleaver way to use presets with different filename pattern.

or is it easy to clone the export module, modify it as my own module and somehow get DT to load it. I dont know anything about DT plugin architecture or if its easy to use.

It just seems like it should be easy to use masks created by DT in GIMP since GIMP masks are just B/W whole frame images.

I think an Export preset is absolutely the answer here. Make the settings you want in the export module, then me and save them.