In my experience, Drummer follows time signatures quite well with the follow function enabled. The project I'm working on today uses cut time, 7/8 & 7/16, and Drummer adapted to the rhythm grouping perfectly on the first try in each case. The preset it adds may not necessarily match what I want stylistically, but the feel is always accurate.
Try one or all of the following:
- In addition to setting 2/4 at the project level, manually add 2/4 event(s) to the signature lane: click on the global tracks button and make sure the signature track is showing, open the list editors pane and click on the signature tab at the far right. In the tracks window, place the cursor where you want to insert the event and press the “+” button in the top left of the signature list editor tab - make sure Time is selected, not Key. The time signature window will open and as a bonus, you’ll be able to specify the beat grouping you want.
- Refresh the regions you’ve already created. Every refresh changes the pattern and it's likely you'll stumble upon a pattern you like.
- Create a MIDI region on an adjacent instrument track with notes emulating the rhythm you want, place that region above a Drummer region, Cmd-U to set locators then set that instrument track as the Follow source. I realize you tried that, but based on what you wrote this might give a better result.
- Drag a Drummer region into an instrument track; it will become an editable MIDI region, then you can just edit/create the rhythm you want. It's not defeating the purpose because Drummer isn't infallible and never claimed to be.
- Click on a Drummer region, engage the follow function to your reference region and select different presets. And/or: (first make sure "keep settings when changing drummers" and "keep drum kit when changing drummers" are both selected in Drummer's "GUI") try different categories, the drummers within and their presets.
Drummer is an awesome resource IMHO, but it can’t do everything, it often needs tweaking. The difference between 2/4 and 4/4 is often less obvious in contemporary popular music, unlike a Sousa march. I often see it added after 4/4 as a way of fitting a long lyric phrase (John Lennon-style). Speaking of, "Ob-La-Di, Ob-La-Da" is my 2/4 reference.