I’m not sure exactly how to explain this which is why I couldn’t find it in google but…
I’m painting directly onto a model with just a white mask, but set to .8 strength, when I rotate the object to reach around the back and continue to paint, if I go over a little part I have already painted that part accumulates therefore isn’t .8 any more. How can I prevent it from going over .8 strength, no matter how many times I paint over the same part?
Err, if I understand correctly, instead of Strength you put your Value to .8 (grey)
Thanks for quick reply Billie,
I adjusted the strength in Brush Settings 
Strength is like brush opacity in other software. It puts color in layers. Good for subtle organic painting.
But when you need a certain value over which you don’t want to go, you adjust color itself. Set Strength to 1 and Value to whatever. It will only be able to accumulate to that value now and not higher
Ah ok, now I’m with you. Thanks Billie.