Neck pocket shim.
I like my guitar to have the strings a little higher off the body of the guitar than some manufacturers set the neck angle to achieve. My old RG3120 is about perfect especially since Ibanez uses the low profile bridges on their guitars. I'm used to playing a Les Paul with the pick guard removed so the strings are way off the body. This matters to me because I don't have the best form and anchor my right hand on the body usually when playing and locate my palm by hanging onto the high E. Weird I know but it's worked for 25 years now. I dig into the strings pretty good too and the pick will bottom out sometimes if the strings are really low on the body.
I am still fiddling with my new Charvel ProMod to get the strings etc. setup like I am used to. Neck shimming for me has always been a process where I use the wide end of various thickness of picks and put them under the neck in the back of the pocket. I find that it's easiest to cut the picks so that the thickness still shows on the part going in the pocket so I know what the thickness is. Then I can find a piece that is thicker or thinner by fractions of MMs and adjust to exactly where I want.
Is there a better way or material to use in the pocket? Am I screwing anything up in your opinion?