Re: Not sure about shimming...
Your action needs to rise slightly between the first and last frets of the guitar or the strings will "fret out". When you pick a string, it vibrates and needs room to move during this vibration. If your action is completely even over the length of the fretboard, your strings will not have the room that they need for this vibration and will "fret out", essentially choking the string off.
I also play with a very light touch and the lowest action that I can possibly squeeze out of a guitar. I have shimmed a lot of necks and have found that a lot of times, shimming does not make much of a difference on newer, quality guitars that are in good shape. I have worked on some late 80's and early 90's model RG's that had factory shims, but noticed that they started to disappear on the later models. With the tight tolerances being utilized in the manufacture of guitars today, I just do not think that you you get the same benefit that you once did by shimming. With a shim, you may find that you just end up with the same action that you had, only now with a higher bridge setting.
If you decide to try it, start very thin, like with a business card cut into about a 1/4" wide strip and place it in the very bottom of the neck cavity (closest to the neck PUP). Depending on the thickness of the material used, you may have to double the thickness of the shim.