Well, you can add one more and make that 21. I definitely want to read your current book, and I'll check out that new version, too. Definitely, look for a publisher to carry it for you--but may I advise that you don't short sell yourself by mentioning that lonely 20. Marketing is indeed a challenge, but there may be more avenues for you to get the word out and claim more readers. The more you can show a potential publisher that you already have an audience, the more likely they will be to invest in your new book.
It's stuff like this that makes me wonder if it wouldn't be helpful to set up a thread here on this forum on writing and/or publishing WWII related family history. There is a challenge to this craft of writing, and many hurdles to publishing--and selling--books.
The thing that really gets me, though, is the fact that not too many of these WWII guys are still left. When they are all gone, someone has to pick up the mantle and continue telling their stories. I know I'm feeling the pull to speak up on the behalf of Frank Stevens, my father-in-law, and his Navy experiences in the Pacific arena.
Glad to have met you here, Rocky. Best wishes on your revised publication!