I think from a troubleshooting standpoint, and if no one has any hard and fast numbers to give, I would start with the lower temperature bandwidth. I only mention this because going too hot can fry the whole clutch, but being a smidge on the lower side, you can still have some that hatch. Overtime, the eggs will also tell you if you are on track. If they are late, then you are a smidge too cool on the temp setting. If they are early, too warm. On the too late and too warm spectrum, the little buggers might require a little assistance in getting out of their shell. Some think you shouldn't help them out and others think you should. If you are hatching smaller numbers, helping seems to work for me just fine. I have the time to devote to the eggs and inspecting each egg carefully for a pip or beginning pip. If there is an impact pip/pip point, I know where the beak is and can use a pair of regular the tweezers to fleck off the shell and get into peeling back a tiny bit of the tough quail egg membrane. Form here you should be able to see the quail beak and get the guy access to air. From this point, if there is blood welling up from your incision, place the egg back in the incubator and wait for absorption, if not peel a little more and slowly chisel away. Once you have the beak open to air, they seem to live just fine, even if they take another day of incubation and your assistance on getting them fully out. Take it slow on getting them out. For those eggs that have not piped/you do not see the impact point where a pip is trying to occur, and you see that most the rest of the eggs have hatched, I would suggest a float test in water that is the same temp as incubator temp. The end that floats is the empty end to work on. Use quail scissors to loosen the shell around the top of the floating portion of the egg, fleck egg shell bits away from the egg, make incision and take a peek. Often these are infertile, but sometimes you actually can SAVE a chick that hasn't, for whatever reason, decided to come into the world on his own yet. I used this today, and had a 100% hatch rate from the fertile eggs, and yes, saved a few that weren't coming out on their own this way. They are healthy, non-deformed, with nothing wrong with them. Perhaps they got stomped on by their eager brethren that hatched out ahead of them, who knows....
Anyways, if you want to research quail hatching temperatures, GoogleScholar is a good resource, and here are some journal articles you might just look through. I can't say if they are open access, or if not, but sometimes skimming through the article abstract gives enough information about what the scientists have had to say about temps and hatching rates:
Well, I hope the rambling gives you some help. =)