GA Driver: It's changed to speed brakes 'as required' because initially it said speed brakes 'full', which has the issue of slow retraction, but also the increase in VLS.
I know you'd never let it get to this, but just out of curiosity on descent (managed) you see a 20+kt speed trend vector, (high on slope, increasing tailwind, whatever the cause) you are already at target 320kt SPD +20kt (say 340 heading for 350kt Vmo. Are you saying you wouldn't use speed brake in the first instance? (Push speed / v/s zero ain't gonna cut it in time), would you be advocating exp desc, or manual flight before SPD brake?