Yeah, I've noticed game have a hard time rendering a lot of people in more open spaces (not only people, even mobs, hunt trains and that one Ixion FATE when I never even saw the boss is forever in my mind), but closed quarters seemed somewhat different? Guess not.
Why I'm asking is, there was already a precedents of big enough events where everyone willing to go was invited, but the house coudn't fit all the participats, so a lot of them was stuck outside and missed all the fun. It does seem to depend on the house size, cuz small ones fill up a lot quicker. And as my FC is planning to hold a similar event, we figured it would be nice to know how many people our medium house can fit in. Guess I'll think about an experiment of some sorts to figure out the exact number.

Thanks for the answer tho!