Sorry but he is very clearly entrenched in the idea that women look after babies, esp newborns and that this is not in the father's responsibility. Father Here to help only, which I'm sure he will do. Help when he feels like it or when yOU will demand it.
There is no 'playing it by ear'. Becoming a father should mean that his responsibility as a father comes first, before his hobbies. And his responsibilities are also to be putbsqid baby to bed, take them for a wal, carry them when they are crying, feeding them, changing nappies etc etc etc.
His responsibility as a partner is also to support you and that means been available (or even better proposing) to give some time off, time together as a family, whatever YOU want that will feel good to you.
I would actually be much more forceful and ask him to agree on what will be his responsibility as a new father and partner with a baby in the house.
Who will get up at night/in the early am/at weekend?
Who will change nappies, feed them etc..?
Who will do the HW, cooking, washing?
How much time is he planning to devote to be a father in his week?
How much is he going to devote to being a partner?
Fwiw, with my first we had no idea what was going to hit us but I knew from experience that I don't deal well with the lack of sleep. So right from the word go, the agreement was that we would take turn getting up at night.
We also agreed that he could carry on with his hobbies, one full day every other weekend plus one evening a week. In hindsight, that was too much as he was also away for work 3 days a week.
You need to establish how you are going to deal with it. Take the long view (would that level of involvement also be OK when you will be back at work/have a toddler?) and don't settle with 'I'm so lucky to see him for a half a day in the week'. He is tnworking away, has all his weekends. He should and can spend more time that that with his family.