..035 isn't that thick and 'perfectly straight' is relative but the average
nibbler will be close to its limit.

One of the most commonly used tools in my shop is the throatless shear.

First thing I would do is make up an accurate pattern showing the centers of
any holes plus at least two tooling holes. I'd lay that out with at least a
sixteenth outside the finish line and do all the drilling in the flat. Then
whack them into APPROXIMATE size with the throatless shear, phasor (ie, plasma
cutter), bandsaw or abrasive disk. Once cut the edges have to be treated so
the pieces will lie flat against each other. They they get bolted together
using the tooling holes.

Now I've got a steel BAR about three-eights thick by 16" long, which should be
pretty easy to bring to finished size using a file, disk grinder, belt sander
or whatever..

I think you'll find that uniformity will have a higher priority than absolute
dimensional accuracy.

-R.S.Hoover