You don't need to spend that much to angle the plow. A diverter valve, and a DA cyl will do that. The fluid from your curl function goes to the diverter valve, and the curl cyl hoses go in one side, and the plow hoses go in the other side. One switch position, the curl works normally. In the other switch position, the lever for the curl controls the plow angle.
The system will go into relief when the pressure builds up to the relief setting. The setting on the relief is there to protect your components from over pressure.
https://www.surpluscenter.com/Instruct/I9-5117-A.pdf