To answer whether to follow Rabbeinu Tam’s opinion, we would need more information, the most pertanent being at which latitude you are residing? If you are as far North as Rabbeinu Tam & his contemporaries resided, then there may be some serious obligation to await 72 minutes. Assuming you live somewhat closer to the equator, and if you reside in the USA or/& Israel this is the case, clearly 72 minutes is way longer than the time it takes to get dark & have 3 stars emerge, therefore some fabricated Chumro cannot override any Chiyuv; This includes absolutely not keeping leather shoes on your feet past regular Zeman on Tischo b’Ov nite, not delaying Channukah candle lighting beyond 1/2 hour from real Zeman, not delaying Seder nite commencement when kids may fall asleep & you may miss Afikomen by Chatzos.
Hence you Besalel are 100% absolutely correct & Halachically compliant!! & both Yungerman1 & Yankee Doodle must apologize to Besalel for their having maligned Besalel’s correct Pesak & statement.