MN Ben, nice work. I can see photos now.
That looks like the way I would make it. Lots of little pieces, and the frame mounts are: one with angle iron, one with a plate, whatever is lying around is how you made it? Nothing like a good pile of scrap steel to inspire design.
I sourced the half links (different project) from the Home Depot bucket under the chain display, I asked if I could have them free as I did not have a big bolt cutter at home.
I was thinking to somehow grab the back of the c-channel frame too, but you beat me to it.
In the end,as time constraints, I will give Torklift mounts a try. Very,very unlike me to not make something, but theirs are pretty nice too.