Using monitor templates saves a great deal of work most of the time.
However, there is no good way of testing without "testing in production".
A sample edit flow to modify a monitor could be: -
- user starts edit of template - create new sandbox version of template
Sandbox version only applicable to devices marked as test - When testing is done and template is ready for production
move (not copy) sandbox to production and increment version number
Would also need version history etc, but first step could just be the sandbox without versioning?