Placing vlan 12 and 13 in the same subet is not possible for us. In fact, we need to have both controllers in 2 different subnets so i can make 2 vm kernelports and make an datastore on each controllers.
The vm kernelports are each in one of the above subnets and each go over an other switch to a different controller. With this setup i have 1 active path to each controller over a different switch. (i have no spof)
This is working all fine, just in case of an takeover i lose connectivity to one datastore.