Just been saying in another thread, not sure whether either of these will work but try these,
1.
Put a volume pedal in your patch, set it to min 50%, but so you can increase it to max 100% with the pedal fully down, set your patch how you want level wise etc.. with the volume pedal at 50%, if its still too qieut go to the mixer and increase both the left/right hand sides (make sure both are panned centrally too), just increase the volume for boost.
2.
Do a dual amp patch, make sure mixer both left and right are panned centrally,
pick the same amp twice, same settings etc... but have one louder than the other,
assign the pedal so you can fade in from the one amp to the other, or even so you have both amps at once