All of this is regarding wooden shafts. I think CF is going to open up possibilities that don't exist with wood. I spent over a month designing my shaft taper when I got a cue lathe. No doubt similar to others but this was mine. Somewhere along the way I confirmed my suspicion, zero taper for an extended length like Earl's shaft was rumored to be doesn't work! Like a fishing rod that flexes in the wrong place that shaft didn't flex until just before the taper over halfway to the joint. There was a sharp crack as I snapped that shaft after thirty minutes of testing. I didn't want somebody to fish it out of the garbage can and have my name associated with it. Dealing with wood, a long zero taper doesn't work. I'll start working down from the other direction.
A conical cue, usually a one piece cue, has exactly the same taper from tip to end of butt. Takes some getting used to but plays just fine with a stiff hit.
Then there is the modified cone or european taper. A fast taper from tip through bridge area but not as fast as near the joint and the area of the butt below the wrap area. Faster taper than a pro taper.
The "pro taper" generally has about one half to one mm taper per foot from tip through the bridge area.
The eliptical taper is a misnomer, generally refers to a compound curve when going from the taper near the joint to the bridge area. This allows more meat near the joint and creates a surprisingly different hit than a single arc transition. Probably more accurately called a poly arc taper but I have never seen it called that.
As should be obvious, some of these tapers can be combined. Also, anyone designing their taper feels free to call it whatever they please including names already in common usage. "Pro taper" is one of the most abused terms of all because it means whatever the cuebuilder or smith chooses it to mean.
I would not copy tapers if the taper was available from the original designer still. A matter of professional courtesy. For tapers that could not be purchased I measured every inch or two and created a similar shaft. I quit doing that except in rare instances. I had put a lot of work into my shaft design, if you wanted a different shaft, go to a different builder.
There is one taper rarely mentioned that used to be very common, the bottleneck. People overusing fine sandpaper or coarse Scotchbrite to clean their shafts, Mr Clean will give the same result, eventually wore the shaft down to where it grew smaller behind the tip into the bridging section until a rapid rise behind the bridging section. An interesting shaft to play with!
This is a brief introduction and every builder also uses their own names or whatever they please. My Pro Taper Poli Conic Cajun Special was of course the best shaft design!(grin)
I don't see why carbon fiber shafts can't have a taper profile on the inside and outside of the tube which should open up a whole world of possibilities including a zero taper outer shaft for many inches.
At present all a player can do is hit a lot of shafts and try to find one they like. Then go to the maker of that shaft and try to get one if they can. However, the shaft you buy may hit totally differently than the one you liked. Carbon fiber should at least offer greater consistency from shaft to shaft of the same brand and model. Remains to be seen. Those of us sensitive to such things may want the same lot number!
Hu