1KPD, I would say your recovered revolver ball patch would need to show a pattern "similar" to this.
View attachment 864692
While E is the optimal example, the others show patches that remained around the ball going down the bore as well. There, now I don't have to produce a comparison patch. Remember, the only thing we are trying to prove is that the patch either does or doesn't remain covering the ball while engaging the rifling after jumping the forcing cone. Not concerned about the patch thickness, powder charge, seated ball depth, etc... but you may want to try different tactics and see if you get different results, for Science. Really looking forward to your experiment.
I'm not sure what the patches would need to come out looking like to prove that they adhered to the ball.
They may exit looking one way if a wad is placed under the PRB and another way if a wad isn't placedt behind the PRB.
I think that the photo examples are speculation since those are what tightly rammed patches look like that exit a rifle barrel, and not ones that are loaded into a smooth revolver chamber and pass through a loose revolver barrel.
I think that it should be admitted that some folks have an expectation of what they think the patches should look like after they exit if they engage, but don't really know what they should look like if they engage the rifling.
The patches may not scrub the walls of barrel the same way in a revolver as they do in a rifle.
This is one simple factor to consider.
If a wad were behind the ball and helping to push the patch through, the patch may show markings that aren't shown without the wads.
That doesn't necessarily prove that the rifling marks were caused by adherence to the ball or due to the wad following the patch.
Just food for thought for the purpose of objectivity.
Perhaps the patches need to be examined under magnification for all I or anyone else knows since they never tried examining revolver patches such as these before.
The patch markings in the photo may be an example of unrealistic expectations due to pre-conceived notions.
As well, different markings or a different dynamic may occur that affects the behavior of the patch if filler were placed under the PRB for all we know.
The proof may be obvious or it may be minute.
Who would really know at this point besides someone who has done a lot of testing or shooting with different kinds of PRB loads and then examining the patches for common or uncommon traits and then comparing them.
One suggestion would be to mark the inside of the patch that's touching the underside of the ball.
That way if the patch gets turned around and captured by a wad that pushes it through the barrel, the marked side of the patch will indicate if the patch had turned inside out or not as it passed through the forcing cone.
That could be helpful whether a wad or filler is loaded behind the PRB or not.
Then a person could determine which side of the patch is getting marked by the rifling if at all, i.e. - the inside of the patch or the outside of the patch.
The inside of the patch should not show rifling marks unless the patch was being turned inside out as it passes through the forcing cone.