I could get the 1" channel which would have a 3/4" interior width. I could then saw it to length.
A bit thick at 1/8", but not too bad.
The 3/4" channel, I would have to chisel (or route) down to 1/2" thick lumber, which can be done.
I'm leaning towards the 1".
Ideally, I would like something w/ legs that are a bit longer - say 1.25" or greater - but this looks like the closest.