I have a question about cluster and multiple shared devices.

I have to add a new storage/controllers to a two node cluster.
I have two DL380 with MSA500 in SCSI, I want to add an second MSA500 in SCSI with two new controllers.

Is it a problem to expand clustered pools between multiple shared devices (not on the same controller) ?
Where is the best practice with the SBD partition in this case ?

Thanks for you help,