User:Legoktm/StopForumSpam effectiveness

It's been proposed to deploy StopForumSpam blacklists to Wikimedia sites. I've done a few checks to see how effective it would be. I'm using the 7 day IPv4 + IPv6 list from 2017-09-08, and the 2017-09-02 globalblocking database dump.
 * Records in globalblocking database: 9,062
 * 7,147 are for individual IPs
 * 1,915 are for range blocks
 * IPs in SFS list: 17,806
 * 68 are IPv6
 * SFS IPs that are already blocked on Wikimedia: 4,223 (23.7% of the SFS list is already blocked)
 * 3,937 were covered by a globalblock range block
 * 286 were covered by a globalblock IP block