never use that method with ball eggs !!! same thing happened to me last year it cost me big time slightly moist vermiculite & then the crate very little water. always better to be dry then too wet!!hope they survive if they go green they are dead.
I have used that method (but with egg crate) for every clutch that I have ever produced. Never lost a single egg bacause of it. I have even used just pure water with no substrate at all and they do fine.