As Chopper mentions: No.
Your drive pool is duplicating the data across the same physical disks in the same RAID6 array. Meaning, you lose more than the two drives, and you will still lose all your data despite the drivepool mirroring.
To do something similar RAID 6+1, you would have to create two RAID6 arrays on the Snapraid and make sure the logical drives you present to your drive pool reside on separate RAID6 arrays and then have the drive pool mirror the data between the two physical RAID6 arrays.
Note: I said similar to RAID6+1 because even that wouldn't be considered really RAID 6+1
edit: So - Did a little more digging on snapRAID. It's not RAID6 at all - so, it can't be considered RAID6+1 because there is no RAID6 component to it. You have individual drives with software double parity to account for double drive failures.
It would still be no because there is no RAID6 to being with.