Shaft flex help player to generate more power & how much flex is depend on how fast our swing with help from frame head weight to create the momentum. But for string tension i think it wont bend no matter how fast we swing it & It only bend on impact with the bird. With that, it makes sense that net play wont be affected from very flex shaft as not much spd & momentum to bend the shaft. But low tension other hand give more power but control would be lowered. If my logic above is correct, then the question is. Would it be very bad that having very flex shaft with low tension? Coz it would be easy to bend the shaft to give more power but as the bird touch the string, the shaft power would be absorbed by the string. Then having stiff shaft with low tension. As we gain less to no power boost from shaft, we can still gain boost from string low tension. But net play & control would be terrible to do as the string is kinda bouncy.
I own and use a Yonex Voltric 0.1DG racquet which has a flexible shaft and is head-heavy. In the scheme of things, it is a budget racquet and is manufactured in China rather than Japan or Taiwan. However, I have strung it with Aerobite hybrid thread at 30lbs which is high tension. This combination of racquet, string and tension allows me to generate great power that is transferred to the strings and the high tension means that I am able to use that power from the strings to precisely place the shuttlecock wherever I want, be it a drop shot just over the net or a smash. To answer your question about whether it would be very bad to have a very flexible shaft with low tension, in reply I must say no. This is precisely the set-up that beginners use when playing as the very flexible shaft means that their swing does not have to be very fast in order to generate power and the low tension on the strings means that they give a trampoline effect and transfer that power to the head of the shuttlecock effectively; the problem though is that there is less control over directing the shuttlecock with precision when playing shots.
So both flex shaft & low tension give power boost. And both flex & low tension is good for beginner to help them in arm power department. But for them who had gain some good arm & wrist, which is better if we want to gain more accuracy control? Go for stiffer shaft but stay on lower tension. Or Stay on flex shaft but do with higher tension.
Start with a flexible shaft at higher tension and see if that allows you to retain the required power - accuracy balance. If not, then move up to stiff shaft at higher tension.
