What wattage are you using for the basking bulb? Also what type of fixture? I use a dimmable dome and for me it makes adjusting the temps so much easier than changing wattage or adjusting the height. As the ambient temps change with the seasons you will probably also have to adjust your temps unless you keep your house the same temp all year long. Some people even use thermostats so you will never have to worry about any of that. 66 is a bit cool for night time temps, anything lower and you will need to get a ceramic heat emitter to bump them up a bit. Personally I would do it anyway to keep it about 70. Your humidity sounds fine.
Good luck with your new beardies. Do you have any pics from the breeder you can show us?