A 2x6 is one of the cabs I'm mulling over for a small, WB-based rig. 4 Ohms could be nice, to take full advantage of the WB's available juice. 8 Ohms would be nice in that it would allow a small-medium-large setup with a 4 Ohm 4x6. The WB should handle both at 2.67 nominal Ohms, and put out... maybe 400 Watts? More? Of course, I could always get a small cab and a big cab without worrying about combining them. That might make sense, even if it doesn't satisfy a certain anal-retentive desire to get three rigs out of two cabs.

(That would be a pretty symmetry, no?)
Anyway, if you haven't tried an HPF and are looking to maximize a small rig, I might look there. I don't think the WB has much HPF built in.