Most visitors online was 4107 , on 14 Jan 2023
The charts can be very confusing but they do make sense with enough study.
Both major companies sell bushings made for each of their reamers. This establishes the bushings OD. Then each of those groups are divided into two other groups by Height and ID (bore).
It's fun (and looks better) to try and pick one bushing group for all of the necessary bushings a clock may need. But often your will need two ODs but rarely three ...
Examples: A Regula 25 can always be fully rebushed using only #2 KWM bushings. Unless it needs a bushing at one or more of chain wheels. Those will require a #3 bushing. Most American clock can usually be fully rebushed using only #3 bushings. The Bergeron system can be used in a similar manner.
You will need to study about any letters associated with the bushing numbers. Some don't mean anything important, some indicate the metal used, etc.
Good luck & bush on ... Willie X