I have installed a two level rotary switch which uses the existing resistor arrays. Problem is that I did the variable gain mod and new amp chips at the same time and I ended up with a non-functioning unit. I think it is from some of the traces I messed up when soldering the gain pot wires. The switch mod seems to be fine. I also had an intermittent power problem before I started and that may have come back (ugh), and the project was depressing so it has been sitting awhile. Right now I would be grateful for a detailed photo of the traces on the back of the circuit board so I can fix that.
I got the rotary switch from Mouser and it works/looks pretty good. It is 100 times easier to use than the DIP switches. You can set the number of positions with itty bitty pins inside the switch. It takes two input signals and routes them to one of up to I think 12 output wires for each. I'll take some pictures.
I realized that the switchable steps are a good idea because you can go in and figure out exactly where you switched and apply a uniform gain to the area in post process, where if you use a pot you can't do this. So you see it going over, turn the knob, and later bump down the wav file up to the point where you switched it.