I agree! I think your suggested rating range is very ideal. I just finished reading this book! I started it about a year ago when my 'standard time' rating was around 1200. I only read half, and though I could understand the concepts, it was still difficult to implement in an actual game. This was because I had to concentrate way too much of basic tactics still, and simply hanging pieces etc... Now at 1400, I got through the book fairly quick, and feel it has helped my game.
The biggest epiphany I had was on the subject of weak squares, due to no pawns being able to guard them! This was something I didn't pick up right away learning chess. Any squares that can no longer be guarded by pawns become hugely important, with or without a piece on them.
In my limited chess experience, I think this is the biggest difference between a 1200 and 1400 player. The 1200 player willing to push too many pawns, too far, too quick (usually creating weaknesses), while the 1400 mainly plays with pieces, only pushing pawns when the time is right to do so!
In the Book Form of this site, The Amateur’s Mind by Jeremy Silman is discussed from time to time. The most frequent criticism goes something like this: I already know what I am doing wrong. While it is true that Mr. Silman does point out common mistakes made my amateurs this book is much more than just that. The premise of the book is that we as Amateurs have developed a number of bad habits, and need to replace these bad habits with better ones. For example instead of making simple one move threats that are easily detected by our opponent, we should be looking at the imbalances that exist on the board and basing our moves on how to improve our position in light of these imbalances.
This book also has rules that help you understand the advantages and disadvantages of the position. For example: “Knights love closed positions with locked pawns. Their ability to jump over other pieces makes the very valuable in such situations.”
The book also has Tips such as: “Don’t ignore your opponent’s threats or ideas. Just because you have a superior or even winning position doesn’t mean there is nothing for your opponent to do.”
For me this book was what helped me to begin to understand positional chess concepts. It also taught me what do to when there are no tactics, and also how to consider the consequences of tactics in light of the resulting position. For example is being up a pawn really worth closing your open file?
I believe this book would be very beneficial for anyone between 1400 and 1600, who is looking to improve their positional understanding.