hydraulic backstay adjuster pressure relief valve setting on 32-3

Thinking about adding a hydraulic backstay adjuster to an Ericson 32-3; seems that the manufactures have gone away from gauges and installed pressure relief valves to prevent over-tensioning of the backstay. Question - what would be a good setting for the valve as to not "drive the mast through the bottom of the boat" or actually bend the boat! Any ideas?

thanks!