1 month old feedings

I pump breast milk & supplement with formula since my supply has never been great enough for strictly breast milk. My baby was born 6.6 lbs & lost a good bit after birth from jaundice. He’s now a month old & 7.7 lbs. my question is, he’s been eating 3 oz ever 2.5 to 3 hours should I bump him up to 4 oz every 3-4 hours? Also, some nights he will sleep 6 hour stretches if I don’t wake him to eat, should I wake him or let him sleep the 6 hour stretch? Thanks for the help, first time mom here!😅💙