Eh, I would say forget about making any more rolls.<br/><br/>The rolls exist just to put a mechanical context to what's going in the entire room. With 300+ participants... it's statistically guaranteed that at least 15 of them get a natural 20 on every question. So no matter how low the students' actual knowledge is... SOME of them know the questions right out. Of course, you have plenty of genin who put actual ranks into Knowledge so that number is a lot higher than 15. Then you have students sharing answers with their team mates, raising that number further.<br/><br/>The answers are in the room and you could get them without rolling a single skill check.<br/><br/>At the same time, the test gets more difficult as more students succeed. A perfect score of 100% ensures that you'll pass... but it also means that you make the test more difficult for your fellow villagers on different teams. People who violate the rules, like the girl that screamed at Azuki's snake, lose a point on their score that they can never get back. Rules are also created on the fly... actually, that gives me something to post real quick..