Ernie - You asked why I had more margin on the inside of the pages. This is what Kindle Create Publishing recommends:

Page Count - Inside Margin
24-150 - .375” (9.6 mm)
151-300 - .5” (12.7 mm)
301-500 - .625” (15.9 mm)
501-700 - .75” (19.1 mm)
701-828 - .875” (22.3 mm)

After looking at a proof copy of the book, I decided that the standard margin was not large enough and I increased it. The great thing about publish on demand is you can order a proof of the book, get the actual printed book in two to three days and make any changes that need to be made before the book goes on sale. If the book is ready, it is on the Amazon site the next day, or two days world wide. And even after the book is on Amazon, if we find a mistake, we can submit new interior or exterior content and the revised book will be available in 24 hours or less.

I am very familiar with the publishing industry. I published a book on color in the late 80s and my stereogram partner Gene Levine and I have had 6 books of stereograms published in the US, UK, Japan and a few other countries. It is a very different world.