Not much more to say tonight. The main disadvantage I've noticed with colour so far is that I have to work out what colour each character's eyes are. It was hard enough to stop thinking of Rena's hair as 'white' and start thinking of it as 'blonde' again... I am so totally going to forget what colour her eyes are before the next time I have to colour them in.
Unrelated: They've released Ikaruga at last on XBLA. Jake is temporarily happy.
One thing I've done with characters I know I'm going to be drawing more than once is create a color palette specifically for them. That way, I can define their eye/skin/hair color and it is always the same. Then if I want to modify it based on light or other factors, it's super easy as I have the base color to work with.
I can't remember what you said you were coloring with, but I know Photoshop allows you to make custom color palettes (that's what I use). Just save the palettes and then load each character's palette when you go to color them in next time.