I'm with Ken, B7KU into the front.
When running my Mesa, I'll use the B7KU primarily as an OD/Distortion pedal, usally for heavier distortion. Or if I'm playing something that has clean and dirty sections I'll have the amp running clean and the B7KU set to a tube-like overdrive, or whatever that song calls for. EQ'd the preamp part of the pedal to thicken the distortion, so it doesn't wildly change the tone. The pedal can get very close to tube overdrive, but you just can't beat real tube overdrive.
When playing a practice amp, I still run it into the front but I'll use the DG for warm tube-like dirt, and take full advantage of the eq on the pedal. I should experiment with running the pedal into the preamp-in.
Still experimenting with the ACC.
In the signal chain, I treat the B7KU like a typical dirt pedals, right after the wah.
My current chain is:
Bass... I mean Thunderbird => Parapedal Wah => B7KU => Boss BF-3 Flanger => Boss NS-2 Noise Suppressor (lots of RF interference near my place) => Mesa
(Strategy footswitch has a tuner-out, which is where my tuner sits)