What size buttons?

I didn't get to the machine tonight, but I did get to have coffee with a friend, go to acupuncture, and write a letter to the editor - so, even though there was no sewing, I did have a productive evening.  I did, however, do a little (and I mean little) sewing research.  One thing that BWOF never does is give you and indication of what size buttons to use.  "Well, use any size you want!" you might say.  But, there really is a "right" size to use.  I couldn't remember what the formula was, but I know that when the buttons are too big or small, or too far away or close to the edge of the garment, something doesn't look quite right.  

So, as I was "dining" on a chicken teriyaki bowl with a plastic fork (I hate plastic utensils, but don't seem to mind with a rice bowl for some weird reason), I decided to look it up in my Readers Digest Sewing book.  I have decided that I need to use my sewing books more, because when I was looking up the button information, I came across this cool zipper with trim idea.  I think it looks retro 60s and would be fun to put in the front of an A-line dress.  Anyway, every time I open up one of my sewing books, I always get inspiration and ideas.

So, back to the button information. 

 Readers Digest says, "The space between button position line and finished edge of garment must... always measure from three-quarters to the full diameter of the button."  So, working in reverse, I measured the distance between the CF line and the fold line of the facing.  This distance is 3/4".  That means that my button needs to be between 3/4" and 1"  If I want to use a smaller button, I really need to move the fold line closer to the CF.  If I want to use a bigger button, I would need to move it farther away.  This is good to know because when I make the same  blouse in the burnout cotton, I have some beautiful buttons that I want to use, but they are probably only 1/2" or maybe even smaller.  I will want to reduce the distance between CF and fold on the pattern piece before I cut.  Now, to find some buttons for THIS version...