Peter Hanley,
As a cuemaker I have tried all manner of ferrules in the search for a "no throw" cue. I have found that the wall thickness, length and how tightly fitted are all factors.
I have also found that a softer brass gives a better feel and less throw. Plastic or fibre (Tufnol) will tend to eliminate throw and can actually "pull" the cueball.
However, even the best cue will throw if the player does not get through the cueball well.
With practice a good player will find the pace at which a shot is played that will result in minimal deflection and therefore most reliable shotmaking.