In my experience, the girls don't usually like getting up before 11am, which is understandable given that they work until 4am. I've seen guys here talk about appointments as early as 9am, but i think they have set those up in advance.
I recently called Cleo around 10am to try and set something up with Penny and got no answer. Called again around 10:30 and set something up for around noon. When I got there, Penny told me that kitchen mama said I'd been calling all morning waking everybody up. Point being, you're not going to get on anybody's good side bugging them too early.