I am putting a rollbar in my 71 duster built for the F.A.S.T. class. I am trying to figure out the lightest, legal bar I can put in.

From reading the rule book I can run 1 3/4" .083 chromoly bar hoop with same size d/s sidebar, no p/s sidebar and equal sized rear braces.
With a 1 1/4" .065 cross bar.

Anybody ever build a bar like this? Approx. weight? Difference in weight of mild steel?
I have 2x3 frame connectors through the floor that I imagine will give it all the stiffness it really needs, so the bar is really only to appease tech.

Thanks guys.