Looking for a way to smooth values between texture channel.

I’m generating a texture at runtime - properly channeled into RGB.
This texture contains a depth render with different heights in RGB (r being the highest, b being the lowest).

I’m looking for a way to take the value of R and progressively reduce the slope to the value of B.

Tried a few shader tricks to approximate it, but it just doesn’t look as it should.
I’m able to get it into a height texture with 3 steps, but it still looks like 3 steps instead of a smooth transition.

Ideally, I’d produce the R/G/B channels with a proper fade already, but that doesn’t work properly because of the scene capture, so I can’t go that route.

Looking for any tips/suggestions or different systems to look at that may spark an idea if anyone has any.

Here is a screen-cap of a sample texture produced.

Red: Red Channel, Pink: Green Channel: White: blue channel

This texture is used as the basis for tessellation height. so the value not fading to black is essentially the reason the material isn’t sloping down.

By “common shader tricks”
red channel - blue channel into lerp 0 to 1.
or into a smooth step with controller values. however, since the resulting texture is almost entirely a solid color, neither of those end up having much of any effect.

Also, I know I can use a material parameter collection - but is anyone at all able to get “Set Landscape Material Scalar Parameter Value” node to work? it seems like the set value is getting ignored.

far from being smooth, but I was able to get better result by adjusting the depth check material (mostly creating an outer fade on it).
Essentially, they all need to fade for this to slope, so I’m working on figuring that out instead.

The end result is pretty convincing right off the bat, so for anyone searching for a similar solution you may want to look into this.
Basically take the inverse of the channel and subtract the positive, clamp, and subtract the other mask.
IF it is done on a PP material with custom depth/scene depth subtraction divide the height you want to check, the results are fairly good without any need to use Power or division.