I shoot tapered shafts. I like the arrow head at the thick end and the nock at he skinny end. I think its pointless to do it the other way around. A tapered shaft does 2 thing in my opinion. One, it allows the arrow to paradox way better when shot, making it fly better. The other is a benefit on impact. With all the weight up front, the arrow punches through the target better. The wide end at the front allows this. If all the weight was in the back, on impact, the resistance to penetration by the target would cause the arrow to flex allot, and that energy is wasted, not allowing good penetration.
So, tapered shafts shoot better and have more penetration energy than non tapered shafts.