ard > you have to listen/accept/follow to anything that comes out of the mouth of a gadol. UNLESS you have a mesora/gadol saying otherwise.
Listen yes, but why would someone follow a gadol from a totally different derech “unless told otherwise”?! In older times, I would happily live in the outskirts of Vilna – without ever being bothered by what Ben Ish Hai is writing – and can be a tzaddik gamur. Were I to have a question, I would go to my local Rav who might forward the question to Vilna Gaon. If I then learn somehow about Sephardi minhagim – would I need to leave my local mishna sseder and start investigating all Sephardi rulings? I don’t think so.
I do agree with you that it is praiseworthy to learn what various gedolim write – and this should lead you to uncover new questions that you then might ask your local gadol and find out what he thinks.