Material of Vortech Rear Subframe

[problemchild]

Does anybody know .....
The tubing size and wall-thickness of the rear subframe on a Vortech FV. I am referring to the section under the transmission. I am reworking a chassis and looking for a reference for minimal integrity for this area.
Also, are there any stringers, diagonals, gussets, or ? whithin the trapezoid that makes up this section of the Vortech chassis?
Thanks!