Well, a break would make the tournaments longer (more time consuming altogether).
I think if even old players like me can play a full hour without break, others should als be able to do that, haha. :) So I would prefer tournaments to stay without a break.
These are just my two cents, but of course you are free to experiment if you like.
Yes, 5min break max.
But 30min (unless bullet) allows only a few games and introduces even more imbalances with the pairings. Bullet gives stronger players even more advance.