Does this work with blogs created with Gravity Forms User Registration Add-On?

I have disabled default WPMU registration on my network. Registration and site creation is only possible with a custom form I created with Gravity Forms User Registration Add-On. I have CAPTCHAs enabled on my gravity form as a precaution. I am not using BuddyPress.

In addition, I have disabled my wp-signup.php page by using this simple code I placed in MU plugin:

http://wordpress.stackexchange.com/questions/85529/how-to-disable-multisite-sign-up-page

Is Anti-Splog still necessary? If yes, does it work with my setup?

Thank you.