overall, though, thinking about it, what would probably be most effective and easy would be, if you're relatively consistent with pressing A (regularizing the turn to time relationship), to figure out about how much time it takes for 40 dittos to go by (with one or a small handfull of trials), and then use that as your time benchmark, with perhaps a tiny bit extra for a safety margin. 'Cause it could be that it's actually far less time than you've been doing...