Run a ladder bar or an Ultralink if you don't want to cut up the rear floor.
I have to dig out my 25.5 specs (My Fiance has tidied up and stashed them away somewhere), I am not sure what you are referring to in regards to the A, B etc spec. I am assuming it would be some of the options with the floor bars?
I have to get started on the bars on my car next week, I will be doing the floor bars first and then on the cage. My floor pan is out of the car already (I bought it like it), and one from a donor car will be getting welded in.