No spectrum is beneficial during the dark period. Green is the only acceptable spectrum you can use to work under that does not affect photosystems l or II during the dark cycle.

Leaf deformities are often an initial sign of pH swings out of range.

As long as there’s moisture, the seedling can come completely out of it’s shell before transplanting so don’t feel any need to rush. Most wait until the tap root is about an inch long. Don’t lay the paper towel flat. Prop the paper towel up vertical so the tap root can form perfectly straight down between the fold.