We have a 3270 cluster (8.1.2) 

Head 2 aggr1 consists of these two multipathed DS14MK4 trays (IDs 1,2):

We want to hot add another DS14MK4 trays racked right above (IDs 3,4):

I've read the 2011 DS14MK4 guide and verified the loop speeds are all set consistently and IDs are all unique.

(note: trays IDs are 1-4 from bottom to top)

Can I simply:

1 -  remove the top two pairs of fiber and transceivers (these go to head 1 (partner))

2 - daisy chain up from those vacated ports to new trays (3,4)

3 - plug the fiber and tranceivers back in on the top tray?

We would then grow (effectively double) this aggr1's capacity

What are the risks ? (2011 guide mentions panic's are possible with loop misconfig)

(we have 60 VMs running on head 2 on a separate loop and aggregate)