I only type using three fingers on each hand. My three left hand fingers rest on A, W and E (in QWERTY) when idle. My three right hand fingers rest on M, L and : when idle. My right pinky holds down shift when necessary, so I can type nearly full speed in all caps. I actually do not use either of my thumbs to hit the spacebar; my right index finger does as it's right next to the spacebar when idle.
I realise this is really weird and it's probably why my thumb starts to involuntarily twitch (in addition to hurting in general) when I use laptop keyboards too much. :(