That's where a graphic EQ can be useful. You can get the tone stack characteristics of the Ch.2 Vintage setting, then simply add in a graphic EQ in your effects loop with everything flat-lined except for whatever bass frequencies you'd like to boost. For example, 200 Hz is infamous for producing mud when boosted, so you might actually cut that frequency by 1 to 3 db (a mild cut) while simultaneously boosting the 100 Hz frequency by roughly the same amount. Now when you dial up the bass on your Recto's bass knob, it will give you more overall bass, but as much as 6 db more at 100 Hz than at 200 Hz.
This means that when you use the Recto's bass knob and dial back on the bass until just below the point where the 200 Hz range starts to turn your bass levels to mud, you will still have plenty of bass at the lower, less muddy 100 Hz frequency range. Done carefully and tastefully, this can yield a Vintage tone, with all its sweet mids, with plenty of powerful low-bass frequency thump, chug and chunk.
In fact, you can take this a bit further by dialing up a few more decibels of 800 Hz mids for a more singing tone, and/or some 1.6 KHz mids for a brighter, cutting boost for solos.
The key is judicious and minimal alteration of the Recto's original sound. Just enough tweaking to customize the Recto's already great tone to your particular taste.
