Is it OK to make “early Shabbos” based on the zman (Plag Hamincha) of the M”A (even though the rav indicated earlier that the zman of the Gra is also acceptable, I was thinking that perhaps both zmanim are acceptable)? This would mean that one davens Mincha prior to the Plag of the M”A and Maariv afterwards.
Should one be consistent and use only one (either Gra or MA) and not switch around? May one switch around in a case of need? May one use the zman of the MA even if when it comes to krias shema he relies on the zman of the Gra?
I suggest you find a talmid chochom to discuss your problems with,