I built my own Silicon version of the Fuzzrite, but uses a 0.0068 for the out cap of the first stage instead of the stock 0.0022. I used plastic-case 2N2222, I don't remember if I chose them for any particular gain. I used a 500K pot for the fuzz/balance/tone control and a 50K pot for volume.
I've never played a real Fuzzrite to compare with my homemade one, but WOW, this thing is crazy! No doubt all the weird behavior is due to the Fuzzrite's out-of-phase stage mixing. Some notes are louder and/or bassier, others seem to almost fade out or degerate into super thin fizziness. First sweet spot on the fuzz knob is around 9 or 10 o'clock, nice fat OD sound with the second stage fuzz layered on top. The middle third on the fuzz control isn't very useful, there's a lot of volume drop (due to phase cancellation no doubt) and the tone is pretty thin. There's another 'sweet spot' around 2 or 3 o'clock where it's the classic buzzy, fizzy, super treble fuzz, beyond that the treble screech is almost unbearable.