Very clever! And that's some obviously good quality mounting hardware. Well done guys!
For me personally, I opted for a floor mount, under the driver's side rear seat:
The primary reasons for this was (1) I wanted to carry a larger sized extinguisher, and (2) I wanted the driver to be able to reach with from the driver's seat, and the passenger to be able to reach it from the passenger's seat. In this location, the driver can reach it with a little work, and the passenger has a straight easy shot at it.
How accessible to do you think the door mount is from either of those positions guys? Do you think someone could realistically reach it from either spot? Or would either have to physically get out of the truck, and open the door to access it?
Again, nice work!