I like the setup. I don't like the amount of bar it takes up with the shoe and factory locations for the bar mount.
Considered mounting the mill to the 1122 spike but no good there.
That leaves a shallow but wide shoe built on a narrow vertical post, three or four sided. It could be bolted or welded to the bar.
I have some U shaped galvanized with the oval holes down the backbone. About an inch or so square. This might work for the beam mill. Also found two foot long pieces of 1 1/2" x 6" 1/4" aluminum C-channel.