Kudos for managing to improvise an effective incubator.

At three days after the first one hatched on its own I would probably cut the rest and just monitor them carefully - adding saline is fine but I generally only add water (stored in the incubator to avoid temp shocks ) and don't bother resealing the cuts as the integrity is compromised anyway and it may prevent you from seeing problems like debris or mould forming in the egg white ( remove it with a q-tip when you see it ) the blood vessels in the egg drain back inside the snake in the final stages so you can use that to make sure things are going well.

I look forward to seeing how they do for you.