Marc, I just got my copy and was a bit underwhelmed, to be honest. I would like to have seen more detail, photos and information. Rob and Harry took the time to really research their subjects and provide lots of valuable information as well as copious photos. Obviously, that wasn't your goal in this case. The book is what it is; a quick read that you can buy for eight bucks.
I think you should follow their lead and produce a real reference book about stencil drums. The time might be right. An acquaintance of mine, Frank Myers of Allentown, PA, wrote a well received book last year about 60's Japanese guitars. Color photos are a must in a book like this. People will want to see the various finishes in color. Frank went to the sources in Japan; the surviving businessmen who made those guitars and interviewed them. He spoke to American distributors and music retailers who sold them, as well as other collectors and experts. His research was thorough.
I know through my own experience that writing a factual book requires exhaustive research and planning. When I wrote my book, there was no Internet, which made the task harder. I used a typewriter and a fax machine, as well as the US Mail and the telephone. Ancient communication. Today, there's so much information readily available online. Good luck should you choose to write another book.