[kdjones2000]

Here is the other part of NASA CCR's:

15.6.13:Mounting Points: The roll cage shall be mounted to the floor area, which includes rocker panels,of the car in six, seven, or eight points. The cage shall not go through the firewall. The seventh and eighth points must attach to the firewall or front fender wells. All cage attachment points must be mounted to plates, or a mounting box (plinth). Each required cage bar shall terminate on a plate with a 360 degree weld to the mounting plate, except as specified in Section 15.6.14.B. There shall be only one (1) mounting “point” per plate. This point is defined as where the “required tube” mounts. All additional tubes mounted to that plate must be mounted as close to the required tube.

15.6.14.B: Tube / Mounting Plate Specifications: Any number of tubes may attach to a plate so long as they are touching each other at the plate. There may be a small gap between tubes to allow welding 360 degrees around each tube. If there is no gap between the tubes, they must be welded around the base as much as possible to form a single figure-eight weld, AND the tubes must be welded to each other for two (2) inches up from the base plate.

I guess that you are close to the 2 inch rule, and if it's a Hanksville Cage, you should be good.