You have any number of suggestions that would work.
Suggestions made so far:
carry a bag (no)
fabric horse / belt loops (only alright proposal so far)
using a weaker bicycle lock with mount, instead of the M18 (no)
put a rear rack on (close, but no. don't want to add a structure larger than the lock itself)
That's it, so far. It's alright if I expected too much, my fault. I don't want to blame anyone here and I am alright to share images of my own custom-made mount as soon as it's finished.
Suggestions made so far:
carry a bag (no)
fabric horse / belt loops (only alright proposal so far)
using a weaker bicycle lock with mount, instead of the M18 (no)
put a rear rack on (close, but no. don't want to add a structure larger than the lock itself)
That's it, so far. It's alright if I expected too much, my fault. I don't want to blame anyone here and I am alright to share images of my own custom-made mount as soon as it's finished.