Yes! This is exactly how I do it now. And yes, it does give the right metronome.
However, it becomes problematic when I go to Score Edit. I can hide the time sigs on every bar, then I would have to hide barlines.
It would be nice to simply be able to set up the grid using numbers like: 4+3+4/16 or even simply 3+3+2, and have the metronome follow.
Digital Performer’s metronome is can be configured exactly like this. (though whether it does custom grids like this I don’t know.)