The really hard part comes after the float test. If they are still moving .... do you open the air cell and assist (some are screaming NO, right about now)... or let them go and wait it out. I have opened and found they have internally pipped but then became shrink wrapped and couldn't get out on their own. In those cases I have helped them by moistening the membrane and opening the membrane further so they could then get out on their own. Of course don't open a membrane with the red blood vessels as they will bleed, just keep them moist and wait. I have also just waited it out, and although nerve wracking, some did eventually hatch some not. It is sad and more than anything frustrating as we anticpate the hatch so much after watching and turning and hoping for 3 weeks and then seemingly nothing happens. I have had some great hatches and some horrible and I did nothing different from hatch to hatch.
I hope yours eventually hatch out. Good luck and keep us posted.