I've got a 80x80x180cm tent and a 185 m3/h, 125mm fan. In hindsight, I would've even taken a bigger one, since a little smell is still coming out, but it's not bothering me.
I've got a 100 m3/h fan left over, if you want it 😉, you'd only need to pay the shipping (prob. isn't worth it for you, if you aren't living here near germany 😆).
(If you still want it tho, just pm me xd)
Anyways, as others already said, 100 might work.