I have and like the Herd book. There is another one out there (Original Challenger and Barracuda) that I thought was wrong in places but it was me instead. For instance, did you guys know they didn't make any 340 Challenger R/Ts in 70, RT were all big blocks? I confirmed that by looking at Galen's white books and sure enough, none are listed. Even so, books are good sources but not always correct and that's why there are revisions.
Anyway, I mentioned the spray can as an alternative, you can (and I did) get it by the quart or pint from Totally Auto too.