This is my stack, but don't be fooled...the top cab isn't just a cab. It's the combo DT25. This means I have a back up should my head play up & I can run both together via L6 link if I want to 'up the power'.
Usually, I just run the 4 ohm outputs from the head into both cabs & don't even switch the combo on, so I just use the combo's speaker, not its amp. I had to order a longer cable for the combo's built in speaker to reach the 4 ohm output on the head as the factory cable isn't long enough, but it's worth it. Lots of options for lots of different gig scenarios. P.s - don't tell my wife. She thinks the top speaker is just the normal cab. She'd go nuts if she lifted the head and saw all those buttons! ;)