Storage spaces error with enclosure awareness enabled: Not enough eligible physical disks in the storage pool to create the specified virtual disk?

Hi guys, 

I'm a bit baffled by this one. I've got 56 HDDs and 8 SSDs evenly distributed over 3 certified JBODs.I'm trying to set up storage spaced and create a mirrored and tiered virtual disk with four columns. My goal is to get this virtual disk clustered and enclosure aware so I have a failover cluster running. Just to prove my point I'm creating a ridiculously small virtual disk. My script is dumbed down for your reading pleasure. 

Setup:
56 SAS HDDs (1 TB)
8 SAS SSDs (200 GB)
3 Quanta JBODs - certified for storage spaces
2 2012 R2 head nodes with multiple paths to storage
1 failover cluster

So, where exactly am i failing to see the error in this? I've been at it for a couple of days now, and getting tiered :-) 

#Get pollable disks (verify contents manually)
$physdisk = Get-PhysicalDisk –CanPool $true | Where-Object BusType –eq "SAS"
#Get cluster storage subsystem
$stsubsys = Get-StorageSubsystem -FriendlyName "Clustered Storage Spaces on Storagecluster01"

#Create new storage pool and enable enclosure awarenes
$stsubsys | New-StoragePool –FriendlyName "ClusterPool01" –PhysicalDisks $physdisk –ProvisioningTypeDefault Fixed
get-storagepool "ClusterPool01" | set-storagepool -EnclosureAwareDefault $true

#Prepare tiers
$ssd_tier = get-storagepool "ClusterPool01" | New-StorageTier -FriendlyName SSD_Tier -MediaType SSD
$hdd_tier = get-storagepool "ClusterPool01" | New-StorageTier -FriendlyName HDD_Tier -MediaType HDD

#Create tiered enclosure aware disk with appropriate free space for fast rebuild
get-storagepool "ClusterPool01" | New-VirtualDisk –FriendlyName ClusterDisk01 –StorageTiers @($ssd_tier, $hdd_tier) -StorageTierSizes @(20GB, 20GB) -WriteCacheSize 10GB –ResiliencySettingName Mirror -NumberOfColumns 4

Removing the -NumerOfColumns argument defaults to three columns and succeeds. That gives a bad overhead on the SSD tier and poorer performance all over. What am I missing here?

edit: on a hunch I removed the cluster awareness parameter on the storage pool and I can now create a virtual disk with 720GB SSD tier and 20TB HDD tier. What about the enclosure awareness is tripping this up?