Milk supply advice

Hey. This is my third kiddo (12 days old). First baby I did formula only. Second kid I did combination of breast milk and formula (I did more pumping than I did breastfeeding but baby had more formula than breast milk overall). With this third baby, I’m trying to do mostly breast milk with breastfeeding and pumping and minimal formula.

So right now with breast feeding I don’t know how much baby is getting….i look for cues and signs to see if baby is full or content etc and I offer the breast frequently especially in the night. I currently pump twice a day (morning and night) and produce 15-18ozs per pump so about 30-35ozs a day. I give baby formula every other day, just two bottles worth (my reason for this is so if for whatever reason I can’t feed my baby, my baby is familiar with formula and won’t refuse food because it’s a foreign taste).

So how do I maintain my milk supply, keep it fairly high. I’m happy to pump out 15+ ozs per session but I will say yesterday was the first time I only pumped 10ozs in the morning and I was barely engorged. I panicked thinking oh no my milk is going down already. So I improvised and pumped in the afternoon yesterday (making it 3 pumps in the day instead of my normal 2) and my grand total for the day was 35ozs so I felt good about that bit worried now that two pumps isn’t enough to maintain 30ozs a day?! Also FYI I offer my boob frequently in the day to “stimulate” milk in a non scheduled manner (on demand, not always at the same time yet still frequently) I usually try to offer my breast first.

How do I keep my milk supply (with the help of pumping) high?? 30-40ozs per days worth?!