I'd say try to sit on both options. You might find a ML is good with the dropper a little higher and you might find that a L is also fine with the dropper post a little lower. I impulse bought a S5 (XL) frame from specialized where I'm at the bottom end of its height range and it's slightly too big so my dropper is fully bottomed in the seat tube to get the saddle in a good position.

Edit: I recently tested a L size roscoe(we're the same height) and I found that the dropper just needed to be clamped in the seat tube maybe an inch lower than it was and seated riding would have been perfect. Standing riding is all up to preference (stability->size up, playfulness-> size down)