Remember, it’s not an instrument amp. It’s just a power stage. It adds gain. You still need a preamp to take care of the instrument signal. Otherwise, the power stage takes line level in and drives down to a 4 Ohm load. The only thing I left out is that the two heads I have also have a little fan. I think you can drive it off the power supply on the amp board.
As far as protection, you could input limit so it doesn’t clip, but digital distortion clipping goes to crap really fast and you can detect that with your ears. I didn’t dig that deep into it yet to see what it’s input stage already has. It’s a fairly complete module. There may be a couple components to add to the input. @terb can likely have some insight.