At the temps you are using for incubation, if any of the eggs are fertile, you will probably be looking at a 75 to 85 day incubation period. The preferred incubation temps for this genus are mid to upper 70’s and temperature fluctuations like you are currently experiencing will not harm Crested Gecko eggs, or most other lizard eggs for that matter. Minor temperature fluctuations are only detrimental to eggs of reptile species that require active thermoregulation of some type by the female. At the preferred incubation temp of between 75 and 80, the eggs will usually hatch at around 70 or 80 days. Also, make sure your vermiculite is damp, but not too wet, as too much moisture can be as bad as too little.

Kelly