As was already shown Abasia Shows Radiant and hides Brilliant
She bred with Achoo who Shows Sparkle and their baby was a Brilliant
So now we know that Brilliant passed from Abasia but what did Achoo pass. Well they have actually bred 3 times and I got a Brilliant then a Radiant and last night a Sparkle
So since we know Sparkle is recessive to Radiant already and Abasia hides Brilliant she passed Brilliant under the Sparkle, from this we can conclude that Achoo also hides the Brilliant, yet to be confirmed from his Dad Frank, since His Mum passed Sparkle earlier today in a backbreed.
In summary Abasia Shows Radiant and hides Brilliant
Achoo Shows Sparkle and must hide Brilliant since he and Abasia produced both a Sparkle and a Brilliant baby.
Therefore Sparkle is dominant to Brilliant and that places Brilliant as the new most recessive Shade.