You only have 49 disks listed, so I am going to echo Glen's comment that you will need a third 92GB EFD to properly create FastCache.  There are two back-end buses on all the VNX2 controllers, and with the number of SSDs you have I will suggest that you engage both by putting the 2nd enclosure on bus #1.  Honestly I wouldn't ever suggest not engaging all the available buses, even without the SSDs.  Other than that I wonder what premium you are paying for the 5600 over what a 5200 or 5400 would cost.  There is more cache and faster CPUs in the 5600 controllers, but with MCX and only 50 disks I would be hard pressed to quantify the additional performance that you will see.  You don't mention the front-facing ports; while I assume they aren't 1Gb Ethernet they could still be more of a bottleneck than the difference between the 5200 and 5600 controller will provide.
Hi people, I'm starting configuring a VNX5600. Some information:  1 bus , 2 enclosure  Disk are: 2      SAS Flash 92 GB 10    SAS Flash VP 366 GB 33    SAS 1,1TB ( 10k ) 4     SAS 268 GB ( Vault disk )  We have FAST CACHE and FAST VP enabler. I want also use mirrorview, clone and snapshot  ( so, I need some space for RLP ).  My idea is:  - Use the 2 SAS flash 92 GB for FAST CACHE ( raid 1 ) so, I'm using just one disk, maybe I'll order a new one for Hot spare   - Create a pool using enabling fast VP :      9 SAS FLASH VP 366GB in a RAID 5 ( 8+1 ) configuration       27 SAS 1,1TB in 3 RAID 5 ( 8+1 ) configuration   - Create a raid group for a RLP  :      5 SAS  1,1TB in a RAID 5 ( 4+1 )       HOT SPARE: 1  FLASH VP 366GB 1  SAS 1,1TB  What do you think about? Many tanks!!  
help configing VNX5600