In judging negative contrast, tonal range and maximum density, criteria used in this book are mostly set for landscape photographers, ignoring that some portrait and fine art photographers may prefer totally opposite quality than what they consider the best. Whereas Anchell's previous Darkroom Cookbook was merely a cut and paste work of new, old and obsolete formulae, this book sells more opinion and the formulae listed are better edited to select only those suited to modern films. This book also discusses a little about stop bath and fixer, and overall, much more valuable than Darkroom Cookbook, since they fully describe the authors' opinion in each formula. Most flash related trouble is poor contact at PC sockets. First, not every PC plug is made the same, so you want to find plugs that are comfortably tight to your sockets.
Sockets are more prone to rusting.
This very thin hard coating built up on stainless steel is not easy to remove with mild chemicals. Put a bit of toothpaste on the socket, and work with your spare plug cord a large number of times. Then, wipe everything with wet paper towel. Repeat until all toothpaste is wiped off. After working, you can carefully blow them off.