which ht pedal for a dirty boost with the stage 60?

[gypsyblues73]

Picking up a Stage 60 this weekend and I LOVE the sound, however, I was looking at purchasing an OD pedal to give solos a boost with a bit more gain. I was originally thinking of shelling out the dough for an old Tubescreamer, or possibly the Zakk Wylde MXR until I saw that Blackstar has their own pedals. Does the HT Boost pedal add any gain? Or would the HT Drive be a better choice for what I'm looking for (a Wylde/Gus G kind of sound)? And yes, I know there's a Gus G model but it costs almost half of what the amp does!