I think using your thumb for Cmd on Mac or Alt on other keyboards (i.e. the closest modifier key to the spacebar) makes sense and feels like less of a position

I think using your thumb for Cmd on Mac or Alt on other keyboards (i.e. the closest modifier key to the spacebar) makes sense and feels like less of a position shift from homerow compared to using a pinky. And in fact I'd find it very hard to hit something like Cmd+Q with just my left hand if I use the pinky for Cmd.