I bought this last weekend, and was in the middle of writing a review, you saved me the trouble! It is a beautiful book, and I agree with everything you said!
Re the cover, I think the red-trail is just to suggest the path of movement across the sun, which a realistic static shot wouldn't do, and the red to offset the yellow of the sun and re-inforce the feeling of heat, looking at the sun etc. It also suggests the look of those old Edwardian illustrations to me. I like the cover, even though it is obviously not realistic, I think it is striking, 'tells a story' and makes you want to pick up the book and look inside.
I think anyone with even a passing interest in the transit of Venus will thoroughly enjoy it.
Anyone in Sydney can attend the book launch on the 24th at the Observatory.
http://www.sydneyobservatory.com.au/...e-book-launch/