FIre Extinguisher Brackets on 991 GT3RS

[Mazdarati]

Want to mount a fire extinguisher to the cage at the back on my 991 GT3RS.

Found a site which have brackets. But which one should i choose ? There are different sizes.
Here is the link to the brackets.
http://www.joesracing.com/series-198182-joes-fire-...!

And this is the link which extinguisher i have.
http://www.f-e-v.co.uk/product/

Want to have same look \/



Thanks