VNX5100 Block Device LUN Sizing

We have a VNX5100 Block Device with a Storage Pool of about 6 TB, and we intend to use the 6 TB for VMFS 5 Datastore.

We also have the plan of expanding the VNX5100 with another 3 ~ 6 TB when it reaches its existing maximum capacity of 6 TB.

I read that it'd better to have the 6 TB divided into 2 x 3 TB LUN with each controlled by a different SP for load balancing.

Also, from VMware VMFS practise, it'd be better to have a smaller LUN with fewer VM in it, if Performance is preferred over Utlilization.

My question is, if I now create a single 6 TB LUN under the control of a single SP, would it create any performance issue?

Would it be a better idea to use smaller LUN instead of a single large LUN???