What should cold lash setting be?

Respectfully, it's the other way around. It's better to have a more gentle ramp than to hit it at a steeper than designed point. I'll always start tight and at the most I'll go .002 looser. But again as has been mentioned, it's a tuning technique.
I would never advocate going looser.

The point of my statement was as follows; Too much lash is better than too little lash, or no lash.