I make it a point to read any articles by Scovill and think he and Brian Pearce are worth the subscription price to Handloader and Rifle. No fluff and no silly sayings and analogies. Just meat.
I am new to hand loading the .45 Colt and totally new to using cast bullets. In addition to going through old magazine articles, I bought Colt's Single Action Army: Loading and Shooting the Peacemaker by Scovill.
It covers about everything I wanted to know about loading cast and has a great section on the .45 Colt ( and other chamberings like the .44 Special). Oversize throats, expansion plugs, neck grip, hardness, velocity, pressure and powders are explained and how they all tie together to make an accurate load.
Great one stop reference for your library.