I've got a Digitech "Jimi Hendrix Experience" modeling pedal that has a Fuzz Face effect in a few of the settings. I had this pedal for a couple years before getting the Mustang III. The JHE pedal works well for me besides just Hendrix stuff. The pedals' presets for "The Wind Cries Mary" and "Little Wing" sounds great for lots of songs and styles, same with the Fuzz Face and Uni Vibe effects.
The way I used to use this pedal was to hook it up in stereo between a 2x12 Marshall combo and a Peavey Delta Blues. To my ears, the effects were incredible, from silky smooth all the way to nasty distortion. With this pedal, I need to keep the gain way down, so as not to run too hot into the guitar amps.
After selling the Marshall and Peavey amps, I had my doubts about how well the Hendrix pedal would work with a modeling amp.
It turned out not to be an issue and I didn't have to change any of the settings on the pedal.
After experimenting with a few amp models, this pedal works the best, IMO, with the Fender 59 Bassman model. I use the Bassman completely dry, no effects, keeping the volume and gain down. Using the volume (not the gain) from the pedal along the Mustang's master volume works out really well.
I use the Digitech JHE pedal now hooked up the same way in stereo using the Mustang III and an 1960's Beltone 1x12 tube combo. I adjust the Beltone's volume to keep a good balance between that and the Mustang ...it sounds really good.
Again, it surprised me that I didn't have to make any adjustments on the pedal's effects, just a couple minor changes with the pedals onboard EQ settings.
So.....if I want a convincing Hendrix type of sound with a Fuzz Face, this is one solution that works well for me, along with using a Strat. I haven't tried this with Humbuckers, but I imagine that I'd have to roll of the volume on the guitar, due to the hotter pickups.