Rigging tension info

R32 what should it be?

I wondered about getting one of those rigging tension gauges.

Most years I just have tightened the backstay until it feels about right, then the side stays, and then the shrouds. Never measured anything, just tighten far enough that when tacking in a moderate breeze the downwind stay should not be slack.

There are only two brands of gauge I've seen advertised. I have 7.2mm diameter stays, so I'd need the bigger size of the American brand of gauge, and that seems to be about £200 or so.

I wonder if anyone knows of any accepted values for rigging tension for  R32?

I thought to make my own gauge and tighten to what i think is right, but could then measure with a homemade gauge and at least get the same tension side to side?

Any thoughts?