Wallace wrote:
I can't help with your G'Mic issues, but removing phone wires/lines for photos can also be done by using the "heal selection", under Filters>Heal Selection, and also the "clone tool".
I've used both methods for this same task.
I would select the areas of the wires and paste them into their own layer, and then use either or both methods to eliminate the wires.
Cloning for the original image to the pasted wire image, and using the heal selection on this same pasted wire layer.
If the selection is saved to a channel, then it can be brought back to try again if it doesn't workout the first time with the original pasted wire selection.
Welcome to GC!

Thanks Wallace,
I've used clone and heal tools... takes quite a bit of work in some images. I was at a photography 'class' where a photographer that uses just her smart phone was showing off an app that allowed you to just draw a line with your finger over what you wanted gone and it figured out what the object was, eliminated it and filled in the background to the point of even continuing the brick patterns on walls all as one move.
I suspect someone has put a similar script/filter/plugin for GIMP out there somewhere. It has been amazing to see the explosion of tools available.
In the meantime, I'm going to have to try your non destructive method. Thanks.