There needs to be a setting for the masking checkerboard to lower the opacity as it's hard to see behind it and when using lighter colors.
Below is an example of what I mean when attempting to paint a decal/masked logo onto a surface.
The problem I had was it was hard to place the logo in between the lines in areas I couldn't see them very well on the mesh, I wasn't able to see the result until after clicking on the surface and the checkerboard was removed. This also caused me to do it several times till it was placed right.
