Cutting sheet steel

I've got some .035 4130 that I have to cut elevon ribs from. 2 inch on
one end, 3/8ths on the other and about 16" long (each one is a different
length). The small end fits against a run of tube, the thick end against
the elevon spar. Both ends have to be shaped appropriately. The sides
of the long runs need to be perfectly straight. I've seen a lot of
options on how to cut aluminum, but the info on steel seems to be more
limited. Here's where I'm at so far.

A shear big and strong enough to handle the job is currently out of my
budget. (though, I keep hearing that the economy is coming back around)

Harbor Freight has a $35 cutting tool that can handle the job according
to the advertised specs. It sorta, kinda looks like an angle grinder,
except that it has a short arm and a reciprocating tooth out one side.
I figure I can drill a 3/8" hole, clamp a 2x4 to each side of the sheet
as guides, and just make a run with the cutter. Anyone have experience
with these things? Do they leave a clean edge?

Another option is to pay a machine shop. If I can find a good shop, I'm
sure to get quality work, but I can't say that I did it and I won't have
a tool afterward. I'm saving that as a last resort.

Are there any better options?

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