Valve Lash - Hot or cold?

Alright - I set the lash with the engine running and hot, and my idle is now able to lower, and is much smoother than before. I still have a bit of a blowby issue; e.g. seeing very light smoking from the crankcase, oil smells like gas - but I'm going to do an oil change as the oil is older than my ownership, and hope it improves. I need to redo my compression test now that valves are correct. Thanks to all for the help!!

Also, I should note, it's about 100x easier to do while running as you don't have to rotate the engine over, and you're only holding the wrench on the rocker for a moment at a time.