Thanks, for the insight regarding the thread plates. Some of mine are missing so making more to replace the larger threaded ones isn't too big a task.
I suspect the "bite" helps to lock the striker in place so probably a good idea to have something that can bite to hold the adjustment once made.
I am seriously considering just cutting the flanges off the striker plates, it is almost like they were added for a different application and somehow got carried over into this truck series by mistake.
