Here is what works for me - its not very scientific - but it works well for me.
I don't measure my balls (LOL). I just put them thru a Freak and see if I can blow it all the way thru - by mouth.
I have tried using a Freak that I can almost blow it all the way thru and found I lost accuracy. I guess I was squeezing them too much.
Keep in mind as the temperature changes so do the size of your balls - recently I had to upsize in the afternoon - this is due to a variety of factors - ball inconsistency, higher temperature, humidity etc.