What should cold lash setting be?

Every Solid Roller that I have ever owned has wide acceleration ramp
lobes. I have run lash from .016 to .030 with no ill effects ever
last 60 years.

I sometimes move the lash around as an experiment to see of
the car wants a larger or small camshaft by how it performs
on the time slip and weather station.

This.

I wouldn’t think twice about going .006” either side of recommended.

Trying different lash is a tuning tool. IMO it would be silly to not try different lash if you are looking to get the most from your combo.