I am looking to make 3 sets of 6 "select list (cascading)", each set type has up to 4 options in the first select list and up to 50 within each of those 4 options. 

To manually implement these fields will take significant time as well as maintaining as the information needs to be updated (using as parts lists). In Jira you can duplicate, copy and/or clone many things such as issues, tasks, automation, users, dashboards, but we are unable to duplicate or clone a custom global field and its configuration to streamline this process. 

This is a very basic task that would become very helpful for many operations. It seems very strange that custom global fields are excluded from this capability.