Project x shafts v S300's

As said above, typically PX launch a bit higher but have a flatter flight compared to TT DG which launch lower but them climb. TT DG usually have more spin, hence the differences.

It is also important to note that PX feels quite different. They were designed to feel boardy, and they do feel rather dull. They are also stiffer than standard rifles of the same frequency. TT DGS300 = PX5.3 approx. KBS are worth a look, as they are designed to combine PX flight with good feel. They need good fitting.

If the OP is ballooning the ball, then X100, perhaps softstepped, might be worth thinking about, as well as PX or KBS.

Mizuno have brought out a shaft optimiser device, used as part of their fitting. This is getting god press for accurate identification of most suitable shaft before full fitting.

I switched from Mizuno MP60 with TT DG S300 to MP62 s with PX 5.5. the two club heads are not very different, so I think it is a decent comparison of shafts. I have a driver speed of about 100-102, 6 iron about 86, and have some hand action at impact. i was spinning the TT DG too much, and since changing, my iron game is just a lot tighter. I can hit a little fade with the 62s, and don't lose it high or left as much. Overall, I am happy with them, although they do feel a bit dull. I have KBS in my wedges and I like those a lot too.

I would recommend the OP getting to a Mizuno fitting cart, getting an idea of what the best shaft might be, then getting proper fitting by someone experienced with PX and KBS. A good fitter can fit these to precise specs in between standard offerings.