I have been working on palm muting too. I have a calibration point. It is the bridge itself. I will lay my hand on the bridge just behind the strings (on top of the bridge pins) then strum softly. I am trying to get control of the pick moving between strings with equal dynamics (loudness, softness) at the same time I am limiting my hand motion by keeping it on the bridge, then when I am relaxed I take my hand that was on the bridge and start sneaking it up past the saddle. This is how I discovered the harmonic clarity palm muting offers. Just a light touch with the side of my strum hand. The bass strings are more forgiving than the trebles, just a fact I keep in the back of my head. It is a practice for sure that seems to get better the more that it is done. I can do it, but I do not have it locked in to the intuitive control section of my guitar tools.