Am I “content” with Schuon’s “interpretatations” of the Trinity? It seems to me your question is tantamount to asking: “Is there more than one way in which to envisage the Trinity?” And of course the answer is yes. Schuon’s interpretations, as you call them—each of which has its precedent in the Christian tradition—help to underscore the fact that a Mystery necessarily eludes the net of discursive formulation. None of these perspectives can capture the Truth on its own, and Schuon knows it.
You mention the distinction he draws between a vertical Trinity, where the Father is understood to be uniquely absolute and the source of the other two Persons, and a horizontal Trinity, in which Father, Son, and Spirit are construed as equivalent—that is, equally divine—whether at the level of Beyond-Being or within Being itself. The first of these standpoints can be found in St Irenaeus, who spoke of the Son and the Spirit as the Father’s “two hands”, as well as in the Cappadocian claim that the Father is the aitia or “cause” of the other two Persons. The second standpoint, on the other hand, echoes the more characteristically western thinking of St Augustine or St Thomas.
Schuon’s discussions of the Trinity are considerably more polyvalent, however, than this relatively simple distinction suggests. You say that you have “little interest” in his “horizontal Trinity”, but this leaves me wondering which “horizontalities” you have in mind, for there are several. I recommend in this regard that you consult a chapter entitled “Evidence and Mystery” in Schuon’s Logic and Transcendence. Here one finds a difficult and demanding, but most rewarding, set of reflections, which conclude with the following summary of “the” horizontal Trinity:
Let us summarize in order to be as clear as possible. First: in the Absolute, which is the Essence, the Persons are not discernible as Persons, although they are comprised within it in a certain non-distinctive manner since the Essence is necessarily the archetype of each possible Person, and this means that the Essence includes aspects without itself being differentiated; in the divine Relative, however, the Persons are present as such, and for man this Relative functions in practice as the Absolute. Second: there is but one single divine Person having three modalities, though according to another aspect the modalities appear in turn as Persons. Third: the three Persons are distinct from one another, but in this respect they are not identical with the Essence. Fourth: each Person is identical with the Essence, and in this respect each is in the Essence, which makes it permissible to say that in a certain way each Person is in the other two or—speaking paradoxically and elliptically—that it is identified with them, the One Essence being each Person in the undifferentiated Absolute.
To repeat what I said above, I do not believe we are to think of this as a list of options, a collection of dishes on some metaphysical smorgasbord, from which we must choose the Trinity that appeals to us most. No, Schuon’s point—his incontestable point, or so it seems to me—is that the doctrine of the Holy Trinity necessarily embraces these multiple, mutually illumining aspects. The Trinity “is” each, while at the same time transcending all.
By the way, for those among my fellow Orthodox Christians who often seek (not without reason) to “absolutize” the Trinity over against the teachings of other monotheisms and who might therefore object to Schuon’s claim above that the Father, the Son, and the Spirit may be construed, from one point of view, as indiscernible and undifferentiated “aspects” of a single Absolute, it will perhaps be useful to conclude by calling attention to a few lines from Prayers by the Lake by St Nikolai Velimirovich:
Eternity exists in eternity just as duration exists in time. In one eternity, O Lord, You were in ineffable sameness and vesperal blessedness. At that time Your Hypostases were the truth within You, for it was impossible for them not to be in You. But they did not recognize one another, for they were unconscious of their diversity. In a second eternity You were in Your matinal blessedness, and the three Hypostases recognized themselves as such.
The Father was not before the Son, nor was the Son before the Father, nor was the All-Holy Spirit before or after the Father and the Son. As a man while waking suddenly opens both eyes at the same time, so did the three Hypostases within. You suddenly open at the same time. There is no Father without the Son and no Son without the Holy Spirit.
When I lie beside my lake and sleep unconsciously, neither the power of consciousness, nor desire, nor action, die within me—rather they all flow into one blessed, nirvana-like, indistinguishable unity. When the sun pours out its gold over the lake, I awaken not as a nirvana-like unity, but as a tri-unity of consciousness, desire, and action. This is Your history in my soul, O Lord, interpreter of my life.