I came down from the front and rear cab mounts vertically with a 1. 5x3 channel. I welded a flat plate on the top with a hole for mounting. I notched the channel toward the bottom for mounting the bars to so there was a 2" vertical adjustment in case I want to raise them later. I welded a 5/8" grade 8 bolt to a piece of 1/4" plate that I then welded into the end of the square tubing at the mounting points. The bolts go into the notches in the channel and are drawn tight with nuts. I also put a gusset on the front vertical channel over to the radius arm bolts for stability.
I will get some pictures and post later on.
Blake