14 SCSI drives - one hot spare - RAID 5

13 active drives (one hot spare)

NSS block size 4KB

I think I can set stripe size (I forget what the default might be)

what would be the fastest setting?

12+parity (13x4=52KB??) OR does it even matter?

many files + 1MB; GIS tiff files 20-50MB; largest files 400MB to 1,200MB.

How to decide ? any hints??

thanks for any help,
Brandon Fouts