Re: ANother New Guitar. . . P/U choices
Well, in the RI Fender Bass VI, that bass cut switch works great (I'm still trying to find the brand of cap they use.
With the TBX control, the roll off happens in a very short range (most of it happening between 5 and 6 on the knob). It does cut the bass. I've installed a stacked concentric pot version on my DC135 (1 MEG/500K pot) and the result is pretty subtle, but it's nice to be able to cut the bass and the top end at the same time. I'm still experimenting with pot and cap values as cutting both treble and bass with, say, a 0.047µF/0.001µF combination (respectively) can just bring the over all level down too low.
In general, I actually like it, and having multiple value caps to choose from is a nice option. It really comes into its own for me with the mid control. Being able to cut the bass and boost the mids gives a warm and thick tone with absolutely no mud; great on the neck pickup, but depending on the the wood and the bridge pickup, it can over emphasize the mids (PG).
Cutting the bass and the mids gives a bit more air to the top end in humbucker, and can make a split humbucker sound a bit more Fender-like, but at lower levels.
So, for me, it's the combination of the modded TBX and the Torres MID/Tone Switch, or the combination of the Stacked Concentric pot and Andy Rothstein Mid control that makes it worth while.
It works, but by itself, it can be subtle, but it seems like you can tailor it a bit for your situation.