Yes-yes, no bantams in breeding lines if the goal is a giant chicken

As I wrote initially, I have been thinking of crossing black Silkies with Ayam Cemani initially and bring in Brahma after that. It's to get Silkies a bit bigger before starting crosses with Brahmas. Does this make any sense - or is it not necessary at all and I could start with SilkiexBrahma crosses from the very beginning?
Also, someone (sorry, I do not remember right now who exactly!) suggested to cross black Silkies with Black Cochins as the first step. What do you think?