Since you requested professional advice I would suggest: shamboosie's book or his online info for coloring treatments.
Incidentally, the book was published in 2002. If I recall correctly, it didn't address non relaxed hair. While some reviewers disagree with bits of his advice , the coloring dos & don'ts & why are detailed.
While he doesn't endorse henna, he covers coloring services including developers/bleaching, what works & doesn't etc.
Just as a disclaimer, I read the book only, continue to henna my hair, & haven't had my hair dyed in years. But, I do think it's a good start for someone searching for how-tos.
Edited by wanderlust87 - Jan 16 2014 at 11:05am