I play metal and just record so turning the bass down to 2 or 3 will let the guitars cut through the mix better and allow more room for bass and kick. I also set the high pass filter to 150 Hz which means that a ton of bass will be lost anyway. Less is more and a fat bass end will muddy up a mix horribly. I also crank the mids to 9 or so, just enough to palm mute nicely but not too overpowering. Then I cut highs and presence way down because there's nothing worse than a totally shrill fuzzy guitar in a mix. It eats up all the high end.From time to time I hear customers complaining they can't get the sound they want and they look at their preset and all the tone knobs are at noon or only slightly deviated from noon. I ask why and they say something like "well, I don't want to stray too far from the defaults".
Amps have controls for a reason. Don't be afraid to get radical with them, especially older amps. Those old amps were crude and not intended to deliver the more modern type tones players today want. For example, if I were to use a Fender model for a lead tone I would turn the bass way down and midrange way up as they get too flubby otherwise.
As an excellent illustration consider Joe Bonamassa's settings:
Bass is all the way down, midrange is almost all the way up. Pretty much how I would dial in that amp (59 Twin or 58 Bassman which are very similar topologies).
As you turn the volume up on these old amps the distortion is coming from the power amp and you need to boost the mids and cut the bass to flatten the response since the power amp's response follows the speaker impedance which is scooped in the mids. Otherwise the bass clips before the mids which causes flubbiness.
That's also similar to how I dial in a Plexi. I crank the mids and lower the bass.
The heavy FAS amps sound way better with ultra high mids and way low bass anyway.
My wish list is a ton of new FAS amps in the future firmware updates. Hint Hint.