OP:
Set a date for Wednesday or Thursday this week.
Now, let's get to the real problem...
You're stepping on eggshells. People who are afraid do that. You're stepping on eggshells - that means you're afraid. Of what, exactly? Well, you're afraid of rejection. You're afraid of rejection because you don't have as much going on for you as you need, much less as much as you'd like.
Getting a date, for you, is the exception and not the norm. This is why you're being so careful. This is why you spend time thinking about "when is the best time to call her." Because you've already made her time more important than yours. And why shouldn't it be? What else do you have going on?
F*ck that sh*t, man. If you were doing what you needed to be doing, you wouldn't need to worry about all that.
See, this kind of advice used to be geared towards guys who had lots of things going for them - a job, a life, hobbies, lots of (real) friends. The only problem with these guys was technique specifically regarding women - they were inexperienced in that regard and so the particulars of their dating habits would f*ck everything up. Things like calling too much. Or being possessive. Or doing everything a woman says, all the time, every time. AFC behavior, basically.
A real Don Juan with ambition and drive in his life will simply not have time to trifle with the details of when to call a woman. He will call when he has time and she will accept his dates because he is worth it.
The problem is that you have no mystique to destroy. Work on that.
Get some hobbies. Master a craft. Be good at something you love. Expand your social circle to include equally motivated people who also love to do those (or even other) things. Make your life awesome and exciting so that you have something to offer, so that your company becomes what women, and people in general, desire.