Q&A for How to Lower the Action on an Acoustic Guitar

The nut is often difficult to remove and is usually glued in place. Replacing the nut can be done by an amateur, however I would leave this job to a guitar tech.

Yes. You couldn't fret a string with this much height at the first fret, and if you did it would be out of tune! On my electrics and most of my acoustics, a 0.60 mm pick (.024 inches) fits snugly held in place between the high E string and the first fret. You can go lower, but do it very carefully a bit at a time - once you cut the nut slot down too far, it's too late.

The intonation depends on the distance of the string from the saddle to the nut and its tension, so if everything else is set up well enough, lowing the saddle shouldn't cause any problem with intonation.

You can find a feeler gauge at most hardware stores, some music stores, and several places online.

You usually only need to adjust it at the bridge. It will change the tuning, but you can always retune.