Physical disk configuration with VSAs

[5y53ng]

I want to get some feedback from the forum regarding physical disk block sizes with the VSA and VMware. For a physical disk array with six spindles, RAID-5, and using local datastores for my VSA disks (not RDM), would a block size of 512K on the physical disks perform than a 64KB block size? 

The reason I ask is that the VMFS 5 block size is 1MB. Is my disk array performing 16 IOs for each VMFS block accessed at 64KB, but only 2 IOs for each block accessed if formatted at 512KB? The VMDKs attached to the VSA are nearly 2TB in size, so would the larger block size on the RAID array help with performance?

Thanks for any feedback.