Doesn't this just change your waiting place from the tee to the fairway? Does it really save any time?
But yes I tee off as soon as the group in front is out of range. It gives me more time to look for my ball (doesn't save a stoke if it take more than 3 minutes, just a couple dollars).
Over the years, in my experience, consistently, REGULAR in a heavy shaft is stiffer than REGULAR in a light shaft. By the same token, STIFF in a light shaft is more flexible than STIFF in a heavy shaft. There must be exceptions, I'm sure.