After eggs go past 7days old the viability decreases. With in 14days I would be surprised if any hatch, but a few could. If you are ordering eggs....lets just say they are gathered the day before shipping and it takes 2days to ship and then you have to let them rest for at least 24hrs(1day)......that would make them 4days old at minimal. So, if they are 4 days old then you would only have 3days to set the rest for the best outcome. Also, shipped eggs don't always have a high hatch rate......30-40% is great, but some people have had anywhere from 0-100%....it is a gamble. The only possible chance you would have to try and keep the extra eggs viable is either: get another incubator, or put them in the refrigerator and hope they hold up. If you do try the fridge, make sure to let the eggs reach room temperature before putting them in the incubator.
If there's any way you can cram all of the eggs into your incubator, do it. Even if they're stacked on top of each other and you have to hand turn them for the first week, go for it. Like Jeslewmazer says, you usually don't get a fabulous hatch rate with shipped eggs, so chances are if you shove all 14 eggs into your incubator, by the time you get to day 7-10 and are candling to check for development, you'll most likely have a few that haven't done anything, and you'll be able to remove them and make some space for the good ones.
The more eggs you set, the more chance you'll have of getting chicks.
I agree, I would try my best to cram them in because of the low hatch rate with shipped eggs. You will most likely have some you can throw out after you candle, or get another incubator. Good luck with your hatch!!