Let me throw this out there and see if I can get some feedback that will change my perception.
Regarding the follow through....(and this will be realy evident in the longer draw shots)
My observation of pros is that on the soft touch shots to normal shots the elbow drops just a little (if at all)...as the shot increases in power (and the stroke gets longer) the elbow drops a bit more
...(I have even witnessed Allison drop her elbow as the power increases)
Part of this I think is determined by forearm length...A person with a longer forearm is going to need less elbow drop to complete a fluid longer stroke....(I fall into a catagory of short arms)
I relatate the cue motion to a car or truck going down the road...If the car is going X mph it will take Y feet to stop...(As X increases...so does Y)
In the stroke of a cue...if you are generating a longer backswing and generating more cue speed...it will take more distance after impact to stop the cue....
My perception (I should point out that much of this perception of stroke comes from the way I learned and taught putting in Golf) is that the followthrough should be a fairly equal distance as the backswing.....As you want to hit the ball longer (more power) you increase your back swing...your follow through will also naturally increase....(but you use the same tempo for both the longer and shorter shot or more or less power )..It should happen farily natrually.
Of course there is a limit to the added power where additional force will need to be applied other than just lengthening the stroke......(break speed)...but you get the idea.
What I find (in pool) is that as the power increases (backswing gets longer).... if I try to keep my elbow fixed (after impact) I run out of distance to stop the cue and I then need to apply "reverse muscles" (or at least feel like that is the case) to stop the cue...This (for me) leads to a very choppy stroke on anything more than short or soft or normal shots.
Again...(I think) that people that have longer arms have an advantage here because they will have longer before the arm folds into itself...(as the hand comes up to the arm pit)
That all being said....My stroke tends to start as a pendulum type stroke, but as the power increases and my forearm runs out of pendulum...Instead of "reversing the muscles" to stop the forward momentum of the cue...I allow the elbow to now drop or "collapse" a bit as the cue is decelerating to a stop.
Anyway...that is just my perception of things.... (currently)....but I am open to suggestions......