It should work. You might want to get some cotton or pillow stuffing to put around the egg to keep it upright. I actually used some jumbo egg cartons to hatch buttons before, and the button eggs were laying on their sides. Just be sure to tilt the carton so the eggs are shifted side to side, not end to end. You would be able to set them on their sides that way.
EAT: I think some of them are round, but none of mine have been.
I just use a regular egg carton. Then I use cotton balls to hold them in place. Pull the cotton ball until it is stretched out some and fit it in the egg cup around the egg so it does not move. Worked good for me!