In the BeePre 1, you could use a single 50K attenuator in place of both switches. In the BeePre 2, that wouldn't work so well, and you'd want something closer to 5K.
[For BeePre2] Perhaps a pair of Goldpoint 2-pole, 6-position selector switches, built up similarly? Are they not make-before-break type? I have a bad course switch, and debating whether to replace with same, or upgrade, if possible.
We initially tried the Goldpoint switches for the first BeeQuiet attenuator and they didn't work properly. I would either diagnose what's going on with your coarse switch or replace it with the same part.