Actually, we do not care for neither full-automatic nor semi-automatic electronic keyers. What we love is our good old mechanical bug keys.
So here is what we really want to take a close look. The red trace shows the mechanical contact closure, and the yellow one is the side-tone signal of 600Hz for the letter U. You will immediately notice that the transition time from dot to dash is rather short, which, of course, is highly intentional, but anyway you can do this kind of thing only with a mechanical bug key.
On the contrary, making a transition from dash to dot very short is quite difficult. The figure shows an unsuccessful case although I tried many times to do so.
So this could be a typical sequence for the letter R, a short space followed by a long space in the letter.