UCLA Waitlist additional comments length?

How long should the additional information section of the UCLA waitlist be? I surely do not want to bore the person(s) reading it with comments the length of an appeal letter, but I also do not want it to be short enough to seem like my message is an afterthought to me. They give you space for 7000 characters, but the example they provide is just a list of updated grades and a simple ‘Hi UCLA!’

Any opinion would be greatly appreciated!