Actually I use both. Especially 73 and later, the factory ones are sometimes more helpful, sometimes less. They are no longer point to point line drawings starting in 73. The disadvantage of the two page 3rd party ones is that they leave out options, often connectors, etc, and the connectors don't accurately depict what how they appear. Nevertheless, the 3rd party ones are often easier to follow, the correct answer is "both"
