I think what he is saying is that the Tone Hammer doesn't work too well if you are envisioning the AGS button as an overdrive to complement the clean "channel." Reason being is that the levels are significantly different.
More so, think of the Tone Hammer as a single channel preamp that can be either clean or dirty, pick one. Doesn't switch back and forth too well.
The Tone Hammer DI is a fantastic piece of gear though. I used one for a long time. I found the AGS circuit to be really good when I dialed it in for a slightly low-hair, vintagey vibe.
I use mine the same way. My GAS wants to know how it will play with a Night Owl Edison through my Quilter BB800.


Like in the blink of an eye. I got very lucky.