Hey Douglas,
Sounds like you're looking to develop a Darkglass bass fuzz. Given the great sound and construction of the B3K I think that's a great idea.
One thing that is clear is that no fuzz is the end all, be all for anyone. I think the two routes to go are to do a fuzz that is incredibly versatile with a bunch of knobs or one that does one or two things really well. Both routes have their advantages and drawbacks.
The only pieces of advice I'd give are these:
- Make it compatible with active basses. It's an easy addition to the circuit and opens the appeal up to a wider group of bassists. Os from Music Electronix/Ziebek did this with all his fuzzes using a transformer based on Jack Orman's ideas.
- Don't base it on the Muff circuit. I really dig Big Muff Pi variants but there are already a ton of very good ones that can be used on bass.
And while versatility is always a good thing, I think you'd benefit from an idea of what kind of tone/music the fuzz would be best suited for. Do you want it to sound synthy? Big and doomy? Vintage? And so on. While I think Iron Ether did a fantastic job of combining functionality and range of tone with the Oxide I'm always wary of fuzz pedals that claim to do everything. Personally I'd rather have one that does one or two things really well.
Just my two cents.