4-month old routines

Question:

Hi,

My son is 4 months old now. On 5x 180ml formula every 4 hours ( last feed at 10pm) sleeps then until 6.30/7am- all good :)

So I am confused about when he should be sleeping in the day:

Babywise says 1 1/2 to 2 hours x3 ( poss dropping afternoon nap) and that feeding times should begin to loosly fit in with ours.

Good old Gina Ford says only 3/4 hour in the morning, 2hrs at lunchtime, then poss 30mins later on.

I am very lucky and he will sleep when put down, makes it clear when he is tried before he gets too teary and self settles very well if he wakes up after 45mins.

I have been giving him a long sleep in the morning (approx 2 1/2hrs) then taking him out after his 11am bottle for a couple of hours then back for a sleep about 1.30/2 but he only wants about 45 mins then. Then he eats again at 3 then we play etc, usually with only a quick nap before bath, feed and bed by 7pm.

What I want to know is whether it is better to have regular length sleeps through out the day, prob ditching the late afternoon sleep ( He only likes 30 mins max then if at all)... or if it is better for him to have a long sleep in the afternoon?? I guess they have an afternoon sleep for a couple of years, does that mean you never get to go out for lunch?! If meals times are supposed to coincide then if he is sleeping 12-2 that doesn't match up.

Please let me know if there is anything from experience I should do/ avoid for long term sustainability. I know all babies are different and not to let a book dictate.