QMK keymap: https://github.com/winterNebs/qmk_fir...
About num rows:   / optimizing_the_number_row_article_script  

Previous video:    • Why I don't use a regular keyboard an...  
Letter frequencies: http://pi.math.cornell.edu/~mec/2003-...
https://www.keyboard-design.com/
https://monkeytype.com/
Jashe Poon typing 200 wpm with 3 layouts at once:    • typing 200 wpm with three different l...  
QMK: https://docs.qmk.fm/#/
Home row mods: https://precondition.github.io/home-r...
My WIP layout simulator thing: https://winternebs.github.io/layout-sim