I took advantage of the modest temps yesterday to feel out a little of what we are discussing. Interestingly, I have to retract a little of what I said before.
When casting a shorter line, leaving a little curl in the backcast works well to smooth out the cast particularly if the acceleration starts smooth and speeds up through the stroke as it should.
However, when airing out a lot of line, shooting some running line into the backcast, and casting the whole fly line it was much more effective to allow the energy in the backcast's loop to fully dissipate in a soft unraveling before reversing it into the forward stroke.
I found that when casting the long cast, the backcast unfurls gently as all that energy is dissipated from the line by the taper and the leader reaches a point of neutrality.
There is no 'tug' here, in fact it's a feeling of lightness as the energy dissipates, at which point a smooth acceleration can begin the strong forward cast.
Putting a clouser on the tippet would create a pronounced tug, but that would be a recoil due to terminal weight and not a function of the cast per se.
Fred, let's take some time to dissect this at Danbury.