Don't know about lucidity and the gap - but I find it nice that you mention it.
To be aware of that gap being there - in the sense of being aware, that it is not the stimulus, which causes a reaction directly - but that you are in there - having the gap to decide, what to do - even how to feel about the stimulus to a certain degree - by way of your cognition, your thinking - for me is the ultimate meaning of freedom.

And we ourselves are the ones to grant us that freedom - or live in the illusion of having no choice*.
I always liked the English word equanimity - nails it on the head.

But sorry - I off-topic your interesting thread here...
Yes - I think being in the habit of being aware of the gap and what it means should indeed heighten the chance of "spontaneous lucidity".
Just I can't contribute a personal viewpoint from experience..

*Not wanting to go deeper into the free-will discussion now, though..