Hi Keith,
It's a pity that you stopped developing the plugin. 'Stop Spammers' is nice and powerful.
In our case would be fine to have an option to disable check for spoofing or disable IP address check at all. We rely more on email verification. Because I believe that we should not complicate life of users with captcha and in case of any moot point we should rely on presumption of innocence.
Btw, IP whitelisting does not work in case of spoofed IP.
Best regards,
Eugene