I made some digital measurements using the HA pic and one from Cinemasterpieces, along with what I measured on mine. Using the 'H' from 'THIS', which is 1/2" tall, I measured the margins on the digital images. The results were close enough to be satisfactory - approx 1.5 'H's along the bottom, roughly 1 horizontal 'H' on both the left and right sides, and approx 1.25 'H's along the top. So no drastic image scaling from what I can tell.
The 2 remaining questions for me then are:
1) should the front and back text along the top be offset? (the front text is approx 1/32" lower than the back text on my copy)
2) should the verso be lighter than the front? (both sides look the same on my copy)
Gaining confidence...
Huge thanks to Jeff and Jason for both public and private discussions, as well as Rich.