Sassafrassin'

[McCreed]

So I’d get these combinations if I’m reading that right:

- N
- N+B
- B

- N+M
- N+B+M
- B+M

But no M in isolation.

Correct?

Yes, that's correct. No way to get middle only without a 5-way switch that I can think of.

Another option could be making a custom control plate that you could mount a 5-way blade switch to. It could be recessed or top-mounted like a tele. The plate would cover any modifications to the body you'd need for the blade switch.

Just an idea...