name servers and dns for domain - how to?

[EricVis]

my name servers:
ns1.domain1.com - IP: 99.99.99.91 (also shared IP for all domains)
ns1.domain1.com - IP: 99.99.99.92
domain1.com set up in Plesk 11, A records added ns1, ns2 and pointed to IP addressses above

how do I set up client's domain (DNS records)

clientdomain.com. NS ns.clientdomain.com.
ns.clientdomain.com. A 99.99.99.91


is this correct or I should use here????
clientdomain.com. NS ns1.domain1.com.
clientdomain.com. NS ns2.domain1.com.