So do you use your right or left thumb to press down the spacebar?

I use my left thumb to hit the spacebar, my right thumb is off the keyboard, like Chaotic.

I'm primarily self-taught. I was in typing classes before, but they didn't really teach me anything of value. It's was only when I started using the keyboard more did I develop a method to typing which rests mostly on my near memorization of the letter locations and subconscious execution of common letter patterns.

As for other digits, my right little finger is exclusively for the enter and right shift key, my left little finger is exclusively for the letters "a" "z" and the left control key.

Jam it back in, in the dark.