Mesh painting four textures with RGBA

I previously asked a question about how to mesh paint with all four channels; RGB and Alpha, but was left with a somewhat unsatisfactory answer than meant that I was required to use the ‘blend weights’ module of the mesh painting tool rather than the ‘Colors’ module. You can see the original thread here:

I find the blend weights module very un-intuitive and it does not work well for me. In addition, using it breaks the rendering of my project, so I won’t be using it until this particular bug is fixed. You can see my thread about that here:

A portion of my material network is shown below. I can paint unique materials on top of my base material just fine using the RGB vertex colour channels, but if I try to use the Alpha channel in exactly the same way, nothing happens - it does not work. I would love to know what I am doing wrong, how to achieve the same result using the Vertex colour alpha channel as I can with the RGB channels? Or is there some kind of limitation?
Like I mentioned before, the blend weights set-up really does not work for me and I would really like to figure out why I cannot use the Vertex paint alpha channel the same way that I am using the Red, Green and Blue channels?
Many thanks,
Matt

Does anyone have a solution for this?

My answer might be stupid and/or prove to be not working.

but if you want to use the alpha channel, do you plug the result into the “opacity” pin of the material ?
Is your material set to “translucent” ?

I guess that if it’s not. It does not “uses” alpha channel.

But this only is a guess.