Don't know. You could try a new database file, and see if you can get past 13 with that one.
Are you talking about saved finds from the toolbar? If so, I wouldn't recommend that option. Better would be to script this. You could use a global field, set as a dropdown, so when a user selects a find it performs that find. Or you could customize the menu bar and have one called finds. All the items in that dropdown could be set to run scripts to perform the various finds.
Even if there is a limit, exceeding that limit should not cause a crash.