Mike is right.

Per the SFI 25.5 Specs. Section 2, point 5,

Where it is not practical to fully weld the windshield/roof bar (#12A & 12 B) and or the main hoop (#10) to their adjacent structure (ie: where the weld is in close proximity to the OEM roof), the use of two 1.75 x 1.75 x .110 plate gussets per affected joint is allowed to replace up to 25% of the weld. Each plate gusset must be fully welded on one side. Two fully welded tube gussets per affected joint, 3/4 x .049 moly or 3/4 x .108 mild steel, a minimum of 4" long may also be used. This option is applicable, only to welds in the OEM roof area.

I'm sure if it's good for a 25.5 cert, it would be good for any random 12 point cage of a lesser spec.