Distributed Bass Array configuration

Please, I don't want to debate the merits of the DBA nor of those who espouse it. I am considering adding two more subwoofers to a system that has two already. To those who use a DBA,I am interested in how you have configured them, specifically--

1. Do you run in mono, or do you split the array to run in stereo?
2. What is your approach to setting phase (delay) among speakers that may be facing different directions and are different distances from the listener?

Thanks!