I load for over 10 calibers and over 30 firearms at one time or another.
I have Speer, Sierra, Hornady, Lee and Lyman books and several powder
manufacturer pamphlets. I have also referred to various powder mfr.
internet sites from time to time.
Lyman is my favorite sourcebook and I'm often tempted to throw the
Lee book in the trash (self-serving and dubious front end with an old
regurgitated data section). The bullet manufacturers are of course
one-way about things, but that's not necessarily a bad thing, if you're
using their bullets. Lyman lists several bullet choices, comments on
how they found performance under their listed test conditons and provides
believable pressure data. Their test rifle, if not a universal receiver, also
often coincides with the one for which I'm reloading (serendipity).
I suppose you can have too much input before settling on a new load,
but I like to compare several sources and don't believe on relying on
one source, including (maybe especially) this forum.