I never said I would. You’re the one who brought that up.
At any rate, I shared this discussion with my pastor tonight and asked him what he understood to be appropriate and what he would do in such a situation, giving him the Pentecost scenario. Father is knowledgable, has bi-ritual faculties, says Mass twice each week, and is a liturgical stickler. So I asked him: “If you were concelebrating at Mass on Pentecost, what color would you wear?” Without hesitation, he answered that he would wear green. I asked him why, and he said “Because I am a Byzantine priest.” We talked a bit more, and he mentioned that in many places the Byzantine priests would not even know that red was the liturgical color for Pentecost in the Latin Rite. He gave the example of going to the Vatican, prepared for concelebration. A priest would bring his vestments, prepared to celebrate the Divine Liturgy. I asked, “What if you get an email telling you to bring red vestments?” He said that he would think that someone had died and they need to be ready for a funeral. The whole idea of wearing vestments of his own rite, but not according to the prescriptions of his own rite seemed strange to him.
I was looking through the internet, searching for some pictures to see what was generally done in these situations and found this. I guess these Eastern heirarchs, including our very own Metropolitan William, didn’t get the memo to bring their Pentecost vestments to the Vatican during Ordinary Time.
Likewise, where are the Pentecost vestments on those Latin bishops at the funeral of Bishop Andrew?
I found well over a dozen images, and not one of them showed what you suggest - a priest wearing vestments of his own rite, but in a liturgical color that followed the Latin rite.