Choosing brakes for AutoX and HPDE

[M-Sport fan]

but from what I read is that the RT700/RS683 has better compressibility and alkalinity (I am probably butchering it, but it's something along these lines) ratings than SRF, meaning it can survive more heat cycles.

The Torque/Prospeed 'claim to fame' is in reserve alkalinity, in other words to ability to combat and neutralize the acids which will form in the fluid when heat and moisture are introduced into the braking system, better than and much more than other high end brake fluids, according to THEIR claims.

I am guessing they do this by having a very high fresh/'starting' alkalinity by using various calcium compounds as an additive (which others either do not add or do so in much lesser concentrations).

The whole compressibility thing I am still a little confused about, as the fluid's actual viscosity/density would have to play into this somewhat, but beyond that, someone will have to explain to me what composition, or 'base stock' wise would have a bearing on whether one fluid is more or less "compressible" than another.