some of the details are up to your own tastes. Like leg color for example. however as draye hinted at, even some of the little details can make a big difference.. again like leg color. If you are set on only yellow legs, it is best to avoid white or blue legged birds in particular.
It is because yellow legs are a combination of yellow general body skin plus Id preventing pigmentation of the legs- allowing the yellow body skin to show through 'unobstructed'.
White and blue legs are white body skin plus Id and no Id, respectively.. the latter being a 'double strike' basically. by the way, white skin is dominant over yellow skin.
Green legs is yellow skin and no Id.
Also another thing- NN flocks are supposedly deliberately mixed for color, which also means the white or blue legged birds *could* be carrying yellow skin gene but there is no way to tell by looking at them,
If you want black and white mottles, use black over the sussex. There is no way to tell if your blacks are pure for the black gene or happen to be carrying the gene for buff.
Apoc, I would guess would depend on your preference of mottling with the black bar next to the white tip(aka mille fleur) or none. I don't really know much about this little detail so this needs to be read up on- hopefully Alohachickens will comment on this? My amateur guess is he would throw mottles with black bars.
If no black is desired, then Tank Dozer and Mouse would be the best ones if my idea isn't so far off the mark.
I kind of like Dozer's color the best for starting Aloha type mottling but he presents the double challenge via white skin and blue legs. Mouse is very close second, he has yellow legs to boot but in that picture he kind of seems rather light in type? I'm guessing production might be or fair value to you- personally I easily get frustrated and give up on birds that might be pretty but are not meaty or lay well...