I use 3" sections from expired bandsaw blades (with teeth ground off) and old transformer laminations for shims. store them with the tool/toolholder when removed.
I use a set of feeler gauge. Fully adjustable and is more secure as there is a full contact surface under the tool and you can tighten down without any worries. You can get sets in various total thickness and lengths from the standard 2' to 6" length leaves/blades.
Pierre