You would select 'Factor presets using adjacent Program Change Numbers. Using default Program Change maps, sending Program Change #0 would result in Bank 1:1, Program Change #1 selects Bank 1:2, … Program Change #99 selects Bank 50:1, and Program Change #99 selects Bank 50:2.
Something to watch out for: Some MIDI device manufacturers number Program Changes in a range of 0-127; others may use a range of 1-128. Everything still functions the same. There's simply a numerical offset to consider.
With the type of setup that you've described, I suggest looking into a MIDI pedalboard like the Behringer FCB-1010. (Roland makes a similar 'board.) Ten 'preset' footswitches, with the ability to send up to 5 Program Changes, 2 static CC values, a MIDI Note On, and 2 relay switches per foot press. Plus 2 expression pedals sending variable CC values, and Up/Down Bank switches.