Handwiring a Kailh Choc keyboard

[mathisart]

I'm trying to handwire a Kailh Choc (PG1350) keyboard by doing something like this: https://imgur.com/gallery/87LfDVI

It seems like the diodes goes into the rows. (I wonder if they can go into the columns instead?) 
Here's the diagram for one particular Choc switch: https://kailhswitch.com/Content/upload/pdf/201915927/CPG135001D02_-_Brown_Tactile_Choc-(1).pdf?rnd=945
My question is: to which of the 2 pins do I attach the diode: is it pin 1 (in the middle of the switch) or pin 2 (the one on the side)? Or does it not matter? 

Bonus question. The following guide says the Choc switches can't be soldered directly into a PCB. Is that true for all PCBs? If so, why?
https://josefadamcik.github.io/SofleKeyboard/build_guide_choc.html