you can either use tube and have the harnesses loop through or weld on plates must be a minimum size I think and the plate must wrap around the rear stays so the weld is only stopping the movement of the plate up the stay and the weight is taken by the wrapping around the stay. Its a job I'm putting off I have to makeup a couple of but will need to get the plates hot and bend them around some scrap pipe. Its pretty clear in the blue book I thought (its been a while since I've read it properly)
PITA is a truck cab dependant on how wide your shoulders are depends if you have to mess about with modifying the corner window or not. or make up similar design to D44
can i weld tabs onto the horizontal then similar to the ones in this pic below (hopefully)