I found skink eggs in the yard while weeding,etc and put them in plastic little container just like you with holes in lid like you I didnt add extra heat as kept them in patio where it was 80 to 90 degrees .
I couldnt leave them as was throwing out the fallen palm tree that eggs were found under

However I noticed when I found them they were in slightly humid area but not wet type humidity so just lightly sprayed them once or twice a day but didnt want it wet in the container.

Either way after month 1 egg died as got fungus the other 2 sprouted little brown lizards not sure if skinks and let them go.
I think your doing it correctly you just dont want it wet or eggs get fungus thats why I lost 1 egg but you want them slightly humid never dry