Is there an issue with putting a batch of eggs in to start and another batch of eggs a week later? The obvious downside is that you can't really get into the incubator to clean it out if there is any mess on the bottom after the first eggs hatch - seems like this could be solved by putting the eggs on little paper trays before hatching.
Rational for this is that I have one chicken I'd like to incubate a dozen eggs from. From my reading - it sounds like your success rate drops on the eggs making it after they have been sitting for a week. Therefore to get a dozen eggs - it seems like i'd have a better shot putting in a half dozen now and a half dozen more when they are gathered.