How much are ur LO drinking at 4 months

Hi mummies, need some advice! My LO is coming 4 months old, and I suspect he has reflux as he spits up milk often and has wet burps etc. from what I googled. Hence we always put him upright 30 min after feeds. We are trying to do lesser quantity but more often now, every 2-2.5 hourly. How much are your babies drinking at 3.5-4 months? When we try 100ml, it seems he spits up lesser and sometimes none now. But after feeds he cries and wants more, if we give more he will vomit or spit milk. What should I do? He’s still producing wet diaper and poops daily. Gaining weight now at 7.7kg coming 4 months old. #1stimemom #advicepls