My 1" cyp fry can eat the 1 mm size, and my multifaciatus colony multiplies on the 1 mm pellets. If I have new fry in my cyp grow-out tank (babies having babies), I'll crush some 1mm pellets before throwing them in.
I do use the Grow formula for baby gobies, cyps, and julies when they're young, but I don't feel it's particularly necessary.
anyway, I feed my tank the 1mm and they all eat it no probs. The vast majority of fish in the tank are juvies and they eat it no problem. Sometimes they'll chew it and spit it out if its too big, but then they eat it again b/c its been broken up from them chewing and spitting it out.