Yes, you should be able to choose 5+1 for your Extreme Capacity tier, with the considerations in my first post.  2 spares for that amount of drives is expensive in resource (capacity) and $$.  Placement of drives is not really important with drive mobility and permanent sparing in the VNX2, so I would put them in the same DAE just for 'neatness'.
Hello,   we have a VNX2 comes with 7x400GB (3.5") FAST VP drives. and multiple SAS and NL-SAS drives.  the storage array consists of : 1x3UxDPE(25x2.5") + 4x3UxDAE(15x3.5") as follows:  DAE#4 : Bus 0 Enc 2 DAE#3 : Bus 1 Enc 1 DAE#2 : Bus 0 Enc 1 DAE#1 : Bus 1 Enc 0 DPE#1 : Bus 0 Enc 0  could you please share with me your thoughts about the best way to be used to place the FAST VP drives ??  should i distribute the FAST VP across Buses/Enclosures ?? should i place all the Disks of the raid group set within the same bus/enclosure? Please consider one disk as a hot spare in addition what type of raid can be applied on 6 FAST VP disks ??   Many Thanks, 
vnx2 with 7 FAST VP disks