I've always used vermiculite. Soak it in water and then squeeze out as much water as you can. I put the shoe boxes with the vermiculite and eggs on a shelf in a closet which maintains temps usually between 80 and 85. I had some musk eggs hatch at almost 90 days last year but I would think 80-85 would be normal. I bury the eggs half way. Make sure you don't turn them once they're put in the vermiculite.
Hope that helps.