Update: My tricky corner cabinet doors finally swing smooth
I've been putting together a built-in for a kitchen redo, and the corner doors were tough. After tweaking the mounting plates three times, they open and close without any issues. I checked the reveal on all sides during setup. It feels great to have it run smooth, and the client saw the improvement.
Mix materials for shims all the time. Laminate samples are my secret weapon, the kind you get from countertop shops. They're perfectly flat and you can stack them for exact thickness. Used a black granite sample behind a hinge last week to hide it. Sometimes wood just doesn't get thin or rigid enough.
Remember fighting with some old cabinet boxes that were just slightly out of square. I spent a whole afternoon shimming and planing just to get the new drawer fronts to sit flat. That stubborn final gap stared at me for hours. Getting everything to line up after that felt like winning a quiet little war. Your post brought that whole messy day right back to me! That smooth swing at the end is the absolute best reward for the headache.