Block size for Index files and for Vault Store files

I am migrating my index and vault store locations from Equallogics to Nimble CS500 and want to create the performance policies on my Nimble volumes. I was wondering if someone might know the write block size for each the index files and vault store files as well as if I would benefit from turning on caching and/or compression.

My Nimble volume will be connecting to a Windows Server 2008 VM via iSCSI. We decided to go to an iSCSI connection rather than VMFS datastore because some of the volumes reach near 1TB of capacity, and also because we can control the performance policies more directly for EV performance with separate volumes than on residing on the volumes of the datastores. 

Thanks in advance for your help!