Fire Extinguishers: Best Setup w/Harnesses?

I’ve read through many of the other posts about fire extinguishers and seems everyone has a different approach. I’m looking to save my/passenger lives in case of fire. I have been eyeing 2x of the assault fire mounts w/kiddie extinguisher. Was going to mount on either side of the rear cage. However, I’m using 5 point harnesses and do not think I can reach the rear ones. I do not have a specific budget as I feel this is an important safety issue.

What setup could I use to react to a fire while still being strapped in?