Is this a formed metal dish?
I didn't notice any pictures of the back side.
If so, is the back smooth (stamped)?
Or does it have a circular pattern in the metal (spun aluminum)?
If it's molded Fiberglas & thermoplastic resin, it'll have ribs.
If you click my avatar, you'll see a picture of a C band LNBF on a 36" dish. (not recommended)

Those support arms are 1/2" conduit.
Think it's the smallest available.
Worked fine, mechanically.
So, if I were doing a BUD, I'd use 3/4 or 1", not the 1/2" stuff!
Also, note the brackets and conduit clamps.
They provide lots of adjustability for only a few dollars!
Strongly recommended.
Not my design.
Something a forum member came up with, several years ago, and popularized by others.