https://imgur.com/a/wyqPSeo (unsure why this is marked 18+, sorry; it's SFW).

You can see my first build (blue) in several of these pictures following similar advice to OP's guide (looping diodes, etc), with one modification where I used copper tape for the columns instead of wires.

Then the first picture you can see how much cleaner the single-switch PCB ends up, and I can assure it was far easier to solder / strip / assemble.