Seymour Duncan Wavelength Solo second source?

[Rollaway]

I have the Multi-source duo version of this pickup and really like. I purchased the solo version with the V/T module in the hopes that I could add a magnetic soundhole pickup as the second source instead of the built-in mic of the duo version and see that there's solder points "H", "G", and "UG" adjacent to the label "Source 2" on the cover. I expect that using a TRS cable will split the two signals. But what I'm not sure of is whether using a mono cable blends the two sources as with the duo...with the volume module acting as the "master" volume, or if I'll need to used the TRS cable. I can't find anything online. Any advice....including exactly what to solder where is most welcome. Thanks!