Treble peaking is easy to overdo when bypassing cathode loads. I wouldn't drop the cathode load of the 2nd stage below the 4.7K, because you begin losing clarity in higher gain settings. I prefer to keep it at 10k, unbypassed. Peaking early in the preamp is good for a classic hotrodded feel. Shelving around 100hz in the input stage is effective. Now keep in mind, that you can create the same shelving frequency with different cathode resistor values by adjusting your bypass accordingly. What changes is the stage bias and symmetry, which will affect the character, not necessarily the frequency response.
For instance:
the 2k7/680n arrangement previously discussed shelves at 86hz, at 6dB per octave.
You can shelve at almost the same frequency (87hz) with an 820R cathode load bypassed with a 2.2uF capacitor.
So what's the difference? Since the stage is biased hotter, and assuming the plate load remains the same, the resulting symmetry and headroom of that stage has changed, and you may like it, or you may not. You simply have to try it out.
