I had the green russian, sounds fat and a lot beefier than the bass muff, I flipped to the sovtek deluxe, great as it has the clean blend to retain lows and the mids too, it is a large pedal though.
Best way to get the small green russian to work is chuck it in with a clean blend.
I had mine in a loop of a boss ls2 with the 2nd channel left empty to preserve lows, if you need extra mids get a cheapish EQ pedal in the same loop after the muff with your mids, alternatively an octave up.
Currently using the fur coat, great sound, very different to the muff and works great on bass but does need the clean blend to really stand out.
Yet to find a good bass fuzz that stands out on its own without the need for extra pedals with clean blends, more mids or octaves.