Very cool tutorial.
But I just wanted to mention something that I noticed.
When you are talking about your artwork size that you work width (600 dpi and the pixel count) you are overriding your dpi settings by manually changing the pixel count. That's why artwork doesn't always fit or is big enough for your pages and probably why you might have issues printing.
If you are creating something to be printed later you want to use the DPI and Inches settings when creating your canvas. The DPI is the pixels per inch and the inches is the overall measurements you want the canvas to be able to print too.
So your settings should look more like this
11 in wd
17 in ht
or something like that
Also, almost all non commercial printers can't print higher then 300 or 400 dpi so there's no point in drawing at 600 dpi because you lose all that quality anyway.
You might as well bring it down to something like 350 dpi to save on the file size. As long as you put in the correct size measurements (inches) then your artwork with always print and transfer in the correct size with the correct quality.
I hope that helps.