I think the option you came up with is a good one, partly because I suspect the main decision is whether one needs a tone bleed or not, and less which tone bleed one needs. On your instrument you have a tone control. On my basses I use a Sansamp Bass DI, that has several active tone controls. On my amp I have fixed, parametric and graphic EQ controls. And if I want to feed my insomnia I can begin worrying about the capacitance and resistance of my cables and their different lengths.

I like the idea of a tester, because it helps with the binary choice of whether to use a tone bleed or not. Once it's in, I am only opening up the guitar if I can't do what I want with all that fancy EQ ;-)