HaRav Moshe Feinstein zatzal writes in Igros Moshe OC 4:105.5 exactly as I have been saying. That one who intends to remain in EY and keeps 1 day YT should NOT wear tefillin Chol HaMoed, and he proves that we follow minhag hamakom even to be lenient on a d’Oraisa. I am surprised that the Gaavad didn’t acknowledge this teshuva.
