I steam the milk in the 600ml pitcher and it usually gets all the way up, almost to the brim and sometimes it spills over. For pouring I dump half in a 350ml jug, maybe go a bit back and forth to integrate the foamy part and then pour in my cup (sometimes I get a decent heart latte art, sometimes it resembles a ball sack).
Yes, Motta 750ml was on my radar. I tried a few years ago a 900ml pitcher but returned it immediately, it was too large