Does this mean that we should tighten the screw until it just touches
the valve stem and stop there?

this where reading my article would be helpful

When trying to adjust the valves on a rebuilt engine, or when working on an engine that has had the heads or rockers off for a few days or when replacing lifters I have recommended the following. Set the valve lash to .006" (I.e. no pre-load). 

o lash cold is preloaded hot so just touching is not the same thing preloading is not worth the trouble it causes I dont preload any of my lifters EVER 

Bob