As someone who has an undefeated design award at state level, I will say quite frankly that you would have to do more than just quantity. Judges focus more on the quality of the notebook, with quantity as generally an ignored or second-handed aspect. Judges have their own beliefs and opinions regarding the design award, you just have to design a notebook that is compatible for all of them.
The notebooks I write are clean with minimal errors. When there is any errors, cross them out with a single line and fix it with your initials. Another key is to have organization; don't be afraid to leave the rest of pages blank if it makes your notebook be easier to read. If you see that you will be moving to a new subject, cross out the empty space of the page with a line from the bottom-left side to the top-right side with your initials. Make sure that the designer has clean handwriting and takes time writing in a manner that would clearly be understandable to the judges. Make sure that the notebook always is written in black ink, and not in pencil. This should be common knowledge to most professional engineering notebooks.
Judges want to see that the students are following the notebook accordingly and appropriately while designing the notebook. I spend a great deal of time explaining the design process that will be followed in my notebook, in which will be used for the design. I will also recommenced getting the rubric and make the notebook in order of the grading material by the rubric.
Notebooks are only an aspect of the design award. Make sure that you have very good interview skills and prepare beforehand giving each person of your team a specific topic to discuss about. Make sure that you try your hardest to not interrupt one another because that will deduct points. Also, by having a design that is unique could even further influence the judges to rate you much better because seeing a unique or "never-before-seen" solution could grab their interest. You can also get the judges interest by not slouching down, be confident as you speak, as well as be knowledged by reviewing the interview section of the rubric to know what the judges will ask ahead of time.
Hopefuly this helps in some way, shape, or form :)