I'm sure a post or the like exists....
If not, I should do one.

Anyone ever seen a post of where a interior marketed (branded) coating was done either on a towel or piece of sheet paper and then after curing, placing a drop or drops of water on it to show it's permeability ?

In my brain, I want to do this with a -marketed leather specific coating- and do a test....I've never done a coating on expensive leather except years ago, on a specific use case of Ivory White.....
To add to the data value of hey, if you coat it and try to apply conditioner to the most expensive leather trim available that you have in your car, the leather conditioner now how this -barrier- that either will penetrate on a macro level if it sat for days or will the coating just completely block it.