I too heard many times, that the prerequisite for the KT degree is to be a trinitarian christian. As coming from a christian and templaristic masonic system myself (the Swedish Rite in Germany), I always asked myself, why this is so. We don't go into the details on how one lives his faith, and our teachings always get blury, when it comes to such details. The determination "christian" means at a baseline, belief in God and Jesus as the Savior. All other details should be left to the theological teachings of the church or group of faith, a brother belongs to. I guess, over 90% of those christian brothers would be trinitarian anyway, because all major churches in Christianity are trinitarian.