Water wetter is not acure. If you are over heating you must find the problem. Just because some racers use it does not give it credability. They run alcohol because it runs cooler, do you switch to alcohol.....would guess not.
Get your hand on an infared temp probe. 10 to 50 bucks all over the place. Check the head at the temp probe and compare to your gauge, check the thermostat housing on both sides of the thermostat. If you start with a cold engine you can actually see when the thermostat opens. Then to the radiator. check the temps of the core all over the place. you can see the flow of hot water from to to bottom. The temp at the top should not be more than 10 to 15 hotter than the temp at the outlet.
If the temp is greater then that, the water is staying in the rad to long, if it is cooler the thermostat is open to long.
One thing about flushing rads....you never get the calcium build up out of the cores.even if you take it to a rad shop. If it is plugged it is plugged. Cures in a can do not cure the problem as much as mask them. Until you can say with certaintly this is the problem it is just guess work.
You will get all kinds of opinions here but only good old trouble shooting and an understanding of how things works will get results.
I have had the same problems on my 41. It is cured, required a new rad......runs 170 all day long in all temp conditions....from parades to desert crossings
Good Luck