adding attenuation beyond a volume control (attenuator) so you can attenuate less before the added attenuator.
are you all nuts?
I would add volume controls to my mono blocks. that solves several things
1. find a level on the amps that works with a level on the preamps that makes you and your remote happy.
2, now you can use any line level signal straight into the amps.
3. any balance issue can be solved by adjusting the amps individually.