Have you tried utilizing the Blend If setting?
How does the Layer "Overlay" work currently?
I'm still trying to get my head around the Blend If settings. I've sent you an email with the file. Thanks for helping me last time with the masking problems.
One can split the Blend If-handles by alt-click-and-dragging and a result like this cane achieved fairly easily.
But personally I would recommend another way (if the structure of the surface is the important thing and not seeing through) but that get’s fairly complicated.
Maybe I have mentioned it already but one can use BlendIf-settings ion a Layer, group that Layer, set the Group to Fill 0% and Cliping Mask an Adjustment Layer to that Group.
If that and the underlying Layer are inside a Group with Blend Mode Normal the Adjustment Layer will only affect the content of that Group.
Hopefully this example (for a "black" and a "white" Curves Layer and the combination of both) can make my point a little clearer:
One possible approach to handling backgrounds that vary strongly in lightness might be applying the High Pass Filter with a largish value.
But that would need some testing.