How many bottles do I need?

FTM expecting mid April and planning on EFF from birth. I’m planning on using ready-to-feed for the first month or so (this may change).

But how many bottles do I need? So far I have 6 of the 8oz Philips. Should I get some 4oz ones? Just FYI if it matters, I do have the baby brezza bottle washer.

Thank you for the advice!!