A couple hatchling feeding questions

[crocsnhots]

I have a few questions regarding my newly hatched baby corns.

I read that feeding is not to be attempted til after the first shed. Can they be fed before their first shed?
If not, why not? (Assuming they'd eat ofcourse)

Do the pinkies have to be 1 day olds or can they be a little larger?
I know of braining, and lizard scenting, are there any other tips I should know of that may come in handy for feeding hatchlings?

Thanks