I don't do quail anymore, but I do incubate a lot of chicken eggs. One thing that may help raise your hatch rate is to stop candling. I stopped doing it because I thought "what if I'm wrong? If I am I'm throwing out perfectly good eggs." The infertile ones just won't hatch and this keeps me from opening the bator over and over.
Also, bobs seem to take forever to hatch. See my thread here: https://www.backyardchickens.com/t/787875/i-have-a-pip
Also, bobs seem to take forever to hatch. See my thread here: https://www.backyardchickens.com/t/787875/i-have-a-pip