The bullet mfg knows more about that bullet being pushed by said powder than the powder mfg knows about pushing said bullet.

That handy piece being known...I always look at both and veer to bullet side.

Simple answer: Pick up the phone.

I don't deviate much from my 'standby loads', so I can't remember the last time that I saw a discrepancy between published loads from the same timeframe (i.e. similarly aged editions of manuals), but the simplest answer is to just call the two and sift out the difference. As an shooter that runs "old cartridges in modern firearms", I end up seeing big gaps between published data from different sources (i.e. .45colt loads in Ruger revolvers, .45-70 loads for Marlins). Not all manuals have "ruger specific" or "marlin specific" sections, so I look at the data there, then make the calls to the bullet and powder manufacturer.

I'd be interested to hear what Hogdon had to say about the overpressure signs with their loads.

I use an average of the sources I have on hand. I think bullet companies want you to load light for liability reasons, and powder companies want you to load heavier so they can sell more powder. Just IMO. HD.