||Their is a full Sugya on this. Just pulling Rav out of a hat will not resolve the Halachah. The only Heter today to pray Arvit before sunset is by relying on Rabi Yehuda, because of the statement in the Gemara, "Deavid Kemar Avid..."
First of all, one cannot alternate between opinions. If you chose to pray Arvit before sunset, you must always pray Mincha prior to Plag Hamincha. Secondly, the Heter of "Deavid Kemar Avid..." no longer applies, since we have pretty much all been following the Chachamim for generations. It only applies to the era when it was undecided and each community had its own way. Now almost all pray Mincha after Plag and Arvit after sunset. The ones that pray Mincha after Plag and Arvit before sunset are completely incorrect.
Look into it thoroughly & you'll see for yourself. It is not a 10 minute Sugya......