version 9 schematic
I'd say the diode swap is a good idea with the NYC muff(2000-2007ish), they eventually fixed it but that was the only official big muff that didn't use normal silicon diodes, and I personally think it sounds wrong. if it has the blue diodes(schottky) and swap those for a normal 1n914, 1n4148.
or red LEDs are really good for clipping diodes too, sounds more like the EQD hoof, gives it a better range of gain on the sustain knob, I also like the hoof style tone caps, swap c9 and c8 to 6.8nF (682) ... it closes the mid scoop if you don't want the mid scoop
all versions schematic history have a look you can basically plan on swapping components out to get closer to some era of big muff you want, I think changing the 1uf caps to 0.1uf caps alone gives it a much tighter sound while still being muffy
mods and tweaks I was thinking next time I get my hands on an NYC I will add both the gate and feedback mod and have like a big muff/fuzzfactory...