At this stage, i wouldnt recommend to fix his feeding schedule, just follow their cues and feed on demand. It maybe tiring as it may sounds but every bb is unique so just take cues from them rather than stopping them if they r hungry.
I started work 2mths back but have been coping well so well, yes can be tiring due to the night feeds but ur body will adjust to it, how amazing. Also note that if u try to fix a schedule now, there will a sleep regression during 4th mth whereby they will wake up more than often in MOTN but it is temporary. I suffered an hourly schedule during this period. Sleep early with ur lo if possible to have quality sleep.