What is the best practise to create Volumes

hi.

i have Dell Equiliser PS 6000 model SAN storage. with RAID 50 Configured. and spce 4 TB

1. i want to present 2TB and 2 TB Volumes to the 2 host servers. is it good to present like this or

2. can i present each Volume separately to each Vertual Machine..???

My friends said 1st method is good practise.

3. and i am using Host IP address to present the volumes is it correct way.

4. if i use Host NIC to present Volumes. then can i use the same NIC as Virtual switch or not.

please give me reply urgent need.

thanks.