When I was learning to perform shaft alignment, we almost always used sheet shim stock and cut the shims we needed for the job we were doing. I, and the guy I was working for, thought that pre-cut shims were and unnecessary expense. What I learned as I gained more experience and began working for other people is that there is more expense involved in cutting shims than in buying a set of pre-cut shims. You need to keep some shim stock on hand for emergencies and custom foot configurations but precut shims save time, lot’s of time. It’s not just the cutting time, but you need to take off the burrs and smooth the edges, not only for alignment reasons, but also for safety reasons. Pre-cut shims are not cheap but the amount of time saved in using pre-cut shims will more than pay for itself. I still suggest that even when using pre-cut shims it’s a good idea to use a micrometer to ensure proper thickness of the shim pack during alignment.