There is a certain torque range you must follow, do not over tighten you won't mess up your gaping but you will "F" up your threads then you are screwed.
What I do is wait for engine to be cold very cold not luke warm, do you thing to do tune up.
When tighten it when you start feeling resistance tighten it up very gently like a little biatch don't over tighten you will f up the threads & will need to re-thread or replace valve cover.
