I have not tried that approach. I use the second channel of the Unleash as the volume boost.
This sounds like a good solution.
When you lower the volume on your guitar switch to the second channel of the Unleash and have it set to a higher volume level.
I have a pedal that does this for me. It works brilliently for a single channel amp.
Yup it's a input pad with a buffer and basically you set the volume on the pedal to a clean sound when engaged. It then has a amp switch out that I send to the unleash for channel 2 which I set louder then channel 1 for to make up for the volume drop. Gives me a clean channel On my single channel amp