He actually mastered echolocation for the role, you just can't tell because it's outside the range of human hearing.

What are those on the D and K keys? I assume it's something you added as a tactile aid to locating your fingers, like home row bumps, but I'm curious what exactly you used.

I keep around a wireless Logitech and just connect it alongside my normal keyboard for things like this (usually just for when IT needs to do something on my computer).