Just to clarify that: the max power will be for pure black.
So, you have 0 to 255 Gray scale values:
0 is white, 255 is black
0 value will be untouched
1 will be whatever your min power is
255 will be whatever your max power is
And everything inbetween will be mapped accordingly
If I remember right, the lightest values in this image were around 15 gray.
It’s far easier, imo, to just up the minimum power than to try and edit grayscale values UNLESS you’re going to just stick with Proofgrade settings and then you can test and say ok - it takes a minimum of 20 gray to punch through the masking, with this particular Proofgrade material preset.