One of my "rules" is I don't pay much attention (none) to load data from any forum expert, range rat, magazine article, gun counter clerk, pet loads web site, or gun shop guru. I still, after 30+ years of reloading, get my data from published reloading manuals. Mostly starting load data and OAL, and use them for reference for max. loads. I do occasionally look at powder manufacturer's websites, but usually double check that data against my manuals. And I ain't missing nuttin'...

The only load data I've considered or used other than reloading manuals is the "NRA M1 Garand load data". Never needed to try a magazine article author's load data...