Exactly 17 upload slots for one CCK field instead of the current 10

Can someone tell me a quick and dirty way to modify a CCK field to change it from the 10 fixed fields I have set up right now to 17 or 18 slots. Note that I DO NOT want UNLIMITED uploads, but rather a fixed number, so they all show up on the content creation page.

I was thinking of directly modifying the DB to do this, but I'm not sure which table(s) to modify.

Thanks!
Jesse