Guestbook 1.5 Anti-Spam

I noted an earlier forum entry asking about anti-spam for Guestbook v1.5. I just added a validation code provided by junkeater.com that works well and has eliminated the multiple spam entries I started to experience. Now I have one unresolved issue. After adding the validation code, I had one very long entry consisting only of multiple lines of URLs and Chinese characters. Is there a way to limit the number of lines, words, or characters in the message that the user enters?

I have never used 1.5 nor have I even looked at the code. I'm sure a variation on the 2.3.1 message length chck could be incorporated just as my simple anti spam could be incorporated. IF I ever get any free time I may take a look.