size of net.inet.tcp.sendspace and net.inet.tcp.recvspace

[Yavuz Maşlak]

hello 
i want to tune on freebsd4.9, My server has pentium 4, 2.8Ghz, 73*4 Gbyte scsi disk (Raid5), 2Gbyte ram. 
it runs apache 1.3x.
For max performance, What  does myserver should be size of net.inet.tcp.sendspace and net.inet.tcp.recvspace or other values ?