If you really make timesig changes on EVERY measure, you can try making a custom action like this:
Action name: Insert new tempo/time signature at every measure
* Move edit cursor to start of current measure
* Action: Set action loop start
* Markers: Insert time signature/tempo change marker at edit cursor
* Move edit cursor to start of next measure
* Action: Prompt to go to action loop start
And check "Consolidate undo points".
Then you'll be able to do what you want a bit faster. After every new timesig change, you'll be prompted to repeat the action. You click on "Yes", and type the new timesig/tempo for the next measure. If you don't want to change anything for that measure, you just click on "Cancel" in the Insert Time Signature Marker screen, and continue to loop.
I have this bound to Ctrl+Shift+Alt+C.