Feeding my 8 week old baby

I’ve been breastfeeding 80% of the day and bottle feed him (breast milk or formula) about 20% of the time. Mostly we bottle feed overnight when we’re both exhausted. But one thing I’m still having trouble with is how many ounces is good for his age group. I was giving him 2 ounces but he was very hungry still and I have started giving him now 3 ounces but I’m not sure if that’s too much or too little? Also when he breastfeeds he almost always eats for 15 min from each breast (so total 30 min).