It never occurred to me that anyone would try to carry out two button pressing actions with the same hand: a recipe for trouble IMO, unless you're an accomplished piano player
I'm with AC here in that the right thumb is for the start button and the left thumb for the idle release: much safer
And don't forget to roll onto the release once you've cracked the throttle so that it will close without restriction when it suddenly catches you with an accelerated start.......
Since there seems to be a ww exercise going on, something over 5,000hrs of playing it this way. But I stuffed up when transposing to the EC120, and I still can't work out why?!!