Just to guess, in one round you could check a 5x5' area for exposed tripwires and other mechanisms that could be discovered by close visual inspection (but not touching). In one minute you could go over the entire surface and find anything that might be a button, lever, or moveable element, but that would be hurried and you might trigger it (i.e. you found a button by pressing it). It would take longer if there are a lot of features (e.g. a bookshelf covered in books and knickknacks), and even longer if you want to examine everything but put it back the same so no one could notice you were there. Say up to 5x and 10x.
Double the time to decrease the maneuver difficulty by two, halve the time to increase the maneuver difficulty by two.