Best way to set up Nameservers, and Shared IP?

Can someone explain how they typically set up a server's main host IP, Nameservers, and shared IP? I typically like to keep 2 IP's, 1 for each nameserver, and I like the shared IP different from the nameserver IP's. This way clients can all use the 2 IP's dedicated to NS1 and NS2 for any nameserver options they decide to run. This then leaves the shared IP for its own use. So a scenario would be: Server IP 111.111.111.111 Shared IP 111.111.111.222 Nameserver 1 IP (For main NS and other domain ND) 111.111.111.333 Nameserver 2 IP (For main NS and other domain ND) 111.111.111.444 This setup takes 4 IP's but then it only requires client domains to use the shared IP, or if they require a dedicated IP they can use one, but still use the general NS1/NS2 IP's. Will mail then send properly and validate as it should in this scenario? Is this a good way to set things up? How are you all setting things up with IP's, Nameserver IP's, shared ip, and beyond?