I guess it would be easier to give advice if you could explain what it is you are attempting to achieve with the segregation of paths to your SAN storage. There might just be a different method to achieve the same results.
I guess there is a lot that I don't know about the setup, but is there any special reason why you think that segregating links FC links to your SAN storage will give you better performance than just allowing all traffic over all of the links? If you want to prioritize I/O on a bit more planned basis, then you can take a look at the 'priority' command, aka "FlexShare" in marketing-speak. That would give you a bit more fine-grained controll over what the NetApp prioritizes on the front side.
I'm not yet very well versed in vseries and I don't know if using 4 links will give you a general boost or not. I guess that is something that one can look up easily enough.