I’ve been wanting to try this a long time, but finally I scored a used Badger Schism pedal and have been trying blending dirt pedals, at least the few I have on hand.

Badger Schism XV
I’ll write more on what particular combinations I got to try, but for now, let me share a few quick tips on how to blend overdrive/distortion/fuzz pedals.
1. Phase inversion switch is very important
A lot of parallel loop type pedal doesn’t have this, probably because its intention was to be a substitute for an amp’s parallel loop, intended for modulation/delay/reverb pedals that come after a gain stage. But be sure to get a pedal with a phase switch if you plan on experimenting with mixing dirt pedals. I won’t go into explaining what phase inversion means (here’s an article on Sound on Sound) but suffice it to say, your blended dirt tone may not sound very good at all if the pedals you’re using happen to have phasing issues.
2. Choose pedals with different frequency ranges
When blending dirt pedals, it’s very easy for one to take over the other. So in addition to careful balancing of volume, you’d want pedals that have strength in different frequency ranges. A treble-boosted tone blended with another pedal rich in low-mid range is a good starting point, so you don’t miss the portion of the frequency range that’s not the pedal’s particular strength. Another good example may be a mid-scooped tone blended with mid-boost tone.
3. Don’t get stuck on making pedals sound good individually
In order for the blended tone to work, you may have to set each pedal to not sound that great on its own, but when combined it sounds great. In one of the above examples, you may want to set a treble-boosted side to sound rather thin, so as not to overwhelm the low end of the combined sound. You may be able to set one pedal to be your base tone, but then the other one may end up playing a strictly-additive role that provides only areas that the main sound doesn’t have. But it may not be possible to have each individual pedal and the combined all sound good.
For me, the beauty of Schism is that it’s configured perfectly for what I was hoping to explore — it has 2 parallel loops and an ability to blend the original, not-sent-to-either-loops signal. I also looked at Wounded Paw’s range of blender products and they have a lot to offer there.
I don’t have a huge number of dirt pedals to try blending, but so far I got to try Lovepedal BBB07, Alairex HALO prototype, Catalinbread Silver Kiss Mk2, Barge Concepts BP-1, and Wampler Cranked AC. The configuration I am liking right now has BBB before Schism boosting the treble, driving HALO and Cranked AC. And those two had phase issues, so a phase inversion switch is on for Wampler. This combination gives me a warm yet articulate treble, rich mid range of Vox, and big but defined low end of HALO. Of course, a video will be forthcoming. 😉