I think 15 is fine. I wouldn't do more than that. btw, I like the forum name its from at the beginning too.
New suggestion:
whenever a post reply is done, it takes to you a screen that doesn't have the messages from the thread. So being one with a terrible memory, I would love to have the message from the thread posted above the box where we type, so we can see what was already said.
And...
How about getting the line return setup normally. That is, I have to enter 2 returns when I want to start a new line. Why not just one return? WYSIWYG is a good thing.
just my 2 cents.