Valve lash.. Hot /cold ? How hot is hot?

The RPM & TF heads on my motors have seen lash open consistently .005"-.006" after running. The safe bet is start .004" tighter cold, then check a few as quickly as possible after shutting down a well-heated engine. If it's still a couple thou shy of your hot goal, then just adjust the difference once it's cooled down again...dead cold, like overnight at the minimum.