So you are crossing a male Sexlink on female sexlink of the same hybrid cross correct ??? Are these the Black tailed type ( hens look like RIRs) or White Tailed type (Hene look like Golden Commets ) And are you SURE these came from White Rocks or are you just going by what a hatchery said ? As most white rock strains especially old strains dont have the correct genes to make sexlinks and hatcheried are known to lie about what they use.
Anyway the reason why this is important to answer your question is becuase wheather or not they are black tailed or white tailed, the Dominant White factor will have to be accounted for if they are white tailed.
And if they did infact come from a White Rock strain then the recessive white factor would have to be accounted for as a quart of the chicks would be solid recessive white if so.
But either way regardless of if they are carrying Dom or Recessive White. The basic pattern can be figured without knowing that. If you are breeding a male Red Sexlink, then he is columbian patterned and split for both silver and gold genes and if you the Sexlink hens would be pure for gold genes so they would produce females with half being Silver Columbian and half being Red Columbian, the males will be half Red Columbian and half Split Silver Gold Columbian like the Sexlink roo you are using.
Wheather or not the parents are white tailed will make 75% of the chicks White tailed if so and if the parents were from a White Rock then Recessive White will be coloring all the color in 25% of the chicks.