Block tubing, got some questions.

Actually I think that is supposed to be reamed, not drilled.
I have always done this with a 5/8 reamer and drilled the oil feeds.
A reamer usually follows the original hole quite accurately. Drilling not necessarily. Imho

I've got a 9" .626 ream for after drilling, trying to ream a hole from .563 to .626 is a big jump.