Three A4 for the full dungeon? I've gone perhaps a bit big, perhaps, since I filled out a whole page of graph paper, ended up with 89 rooms (10x10 feet for the smallest to 90x90 for the center of the main faction, the red dragons), with 17 potential connector points to other dungeons.
And, for readabilities sake, I was gonna seperate it into three seperate floor maps, as I used a lot of staircases and interesecting directions and stuff that isn't really readable on it's own.
Well it's not a hard limit. Like I said, it would be just a hypothetical limit in case you want to keep things manageable. If you're inspired to make something bigger don't let me stop you!
That's not quite what I meant. With the way I'm putting it together I'd expect two/three more rooms per floor, which would total roughly 8-12 more rooms, with the last one being just the central chamber.