You can wake baby as often as you need - it just depends on your body how often that needs to be. If baby will not wake or will not nurse and you need milk removal, I suggest hand expressing or pumping just enough to feel comfortable.

Generally newborn babies nurse 10-12 times or more a day, so generally we could say that is the overall frequency of milk removal a mother's body might need. Since you have a large breast storage capacity, baby may not cue to nurse that often (because they get a larger meal each time they nurse) but more importantly you might not feel the need for expression that often...and in that case I am not sure what to tell you, because usually I say "go by how you feel" and it might not apply in your case. Maybe at least until you are completely recovered from the mastitis and the plug has cleared you can have more frequent milk removal but then if you like, decrease it later.