Nice proof, it does indeed count as a proof.
Your logic is correct Pic one proves Heidi hides the Ruby tipped black.
On mating Heidi with Rudy for the second time, the kitten has Rudy's shown Tangerine tipped white.
So Heidi's ruby tipped black has to be hiding underneath it.
Pic one proves Heidi hides the Ruby tipped black.
Not sure if my logic isn't jumbled some days, so I did wonder.