Regarding the original question about the ripples or “puckering” of the cover near the spine...it can be corrected. Depending on the amount of glue applied to the spine, each book can exhibit different amounts of puckering. In some extreme cases the paper has been stretched so bad, it can never really go all the way back and remnants like light creases will remain, even after multiple pressings. In the overwhelming majority of the cases, the book will press out nicely if done by someone experienced. If not you can crush the spine, cause the staples to pop through the paper or cause the glue from the spine to migrate further into the book.
I hope to post after pictures of the book I used as an example tomorrow. It is in the press now and I will leave it overnight.