Modding Randall MTS Plexi module

[Bukak65]

Hi,
Does anyone know how to mod these? Would like to do a 3way toggle for gain and thicken up the sound a bit. Any suggestion would help. I would like to end up with a hotrodded plexi and a Cameron (Atomicaish) modded 800. I know its a tall task.
Thanks in advance,Plexi_PCB.pdf

[trevorus]

Wow, that is just a board layout. It doesn't actually give many clues as to what is actually going on. It should be relatively easy to do, but we need a real schematic to point you in the proper direction.

[Bukak65]

Just added schematic to post