One of the higher regarded Big Muff derivatives out there, the Mk III is Skreddy’s latest version of their Mayonaise BMP. On the board is a dip switch which allows you to switch in or out 2 extra capacitors to the tone section. You could wire these as external SPST switches (you’ll need 2 of them) if you like. I used my Triangle Big Muff layout as a starting point, but there are several changes so the two aren’t interchangeable. But like the Triangle layout, this one is designed for solder-side mounted right angle pots and should fit just fine in a 1590B.
