You should have got some plywood and cut a small sheet to mount the bottle to. I have done this in numerous cars and it holds up very nicely, and allows you to run the bottle the correct direction. And also, if you are careful you can go through th ecarpet and make it look cleaner too.

Last suggestion i have is about the mounting location for the switch. Personally I think the easiest mounting place for the switch is next to the e-brake in one of the plus pieces. It is so easy to shift into second and go straight to the switch without any thought.

Anyways, it looks nice, really clean install and nice engine bay man. Enjoy it, I know i loved mine