*I had originally composed this post at 9am this morning but because of AZ's servers burping, belching and otherwise being unresponsive, I wasn't able to post until now.*
When Predator's engineers designed this shaft, they incorporated a taper that would contribute to (and complement) the L/D characteristics they were seeking. I'm pretty sure they didn't just guess at it or pick one at random. They found and settled on, the taper that works best for this shaft.
No one can argue with what you prefer. You want what you want. However, be mindful that any alteration of this shaft will NOT be a move towards improving it's L/D characteristics. It was designed correctly just as it is.
If you can understand and accept this then you are free to do whatever you want with the shaft. A T/D to 12.5mm won't void your warranty but going below 12.25mm will. It's up to you how much value you place on your warranty.
OK, so now let's look at 'lengthening' the stroke-zone (taper).
Once the tip is down to 12.5mm, at some point along that shaft's length you're going to have to get to 21.3mm, the avg. joint diameter. You can keep moving that back towards the jnt. but the transition angle gets steeper as you do. I've heard it referred to as a 'speed-bump'.
The key to any good taper is to allow the increase in the shaft's dia. from tip to joint without being noticeable or restrictive. Predator shafts do this quite nicely as do SouthWest and a few others.
Another result of lengthening the taper will be the altering of the flex-point. This is where you will notice the greatest reduction in the L/D characteristics. As the flex-point is moved further back towards the joint, this now leaves more of the shaft in front of the flex-point. This in essence, is the equivalent of greater front-end mass. The greater amount of shaft wood that has to move for the tip to get off the ball, the slower it will do it. This is where the L/D characteristics start going out the window. Just doing a minor/moderate T/D can have beneficial results by removing front-end mass but if in the process, the flex-point is moved rearward, any performance gains are nullified.
Consider the 'Z' shaft. It has a more conical taper than the 314. The 'Z' shaft has lower L/D characteristics because it's flex-point is nearer the tip thereby allowing the tip to get off the ball quicker. However, not everyone prefers this taper. The 314 has a more comfortable taper, for most, but doesn't get off the ball as quick as the Z because of the altered flex-point. You can 'toy' with the physics but there will always be a trade-off.
I've heard many people complain about the cost of Predator shafts. What I think that they fail to realize is that the cost of this shaft is not based on the cost of the mtrls that are used to manufacture this shaft but the engineering that went into designing this shaft. At the end of the day, it's a fair price to pay for having the best L/D shaft in the world. But I digress.
You're certainly welcome to do whatever you like with your shaft, it's yours to do with as you please. But since you've asked the question, I thought I'd point out what you might expect as a result.
