Chassis Tubes and RHS's- dimensions and steel type

[Stevieweavie]

What size tube and rectangular (or square) hollow sections are typically used in an F2 chassis, in both the bikes part (headstock to swingarm pivot) and passenger/fuel tank platform, and what sort of wall thickness, plus what material - T45, chrome-moly or mild steel. No need to get your hacksaws out if you don't know, hopefully a chassis builder will come along. Also, is elecrtic TIG or MIG welding generally used or bronze welding