There is a nice new (undocumented?) change to time signature handling in the recent Logic Pro X 10.3 update.
Time Signatures in Logic Pro X 10.3
Clicking on the time signature in the LCD now brings up a new pop up menu with a list of common choices.
Clicking the Custom option at the bottom opens a pop over to create custom time signature values.
Now, you may notice that your list of values doesn’t look the exact same as mine. That’s because the custom time signature menu that is displayed acts like a “recent items” list. The last 10 defined custom time signatures are shown in the menu.
I think this new pop up menu is a great way of simplifying the casual use of multiple time signatures that will probably suit 99% of us 99% of the time. Simply position the Playhead, choose a time signature, and it is automatically inserted at that position. Repeat as needed, and you’re done! No need to open the Global tracks or Signature List; you can create and enter custom signatures straight from the LCD. To delete one, simply change it to the desired value you want to revert to. However for more complex management of multiple signatures (moving them, copy/pasting to different locations, etc) the Global Track and Signature List are necessary