How very Clintonesque of you. Please not each that the word "estin" is used. "Eimi" isn't used once.
Jesus said it Scripture recorded it, and I believe it.
No, it is not I who pins his entire theology of the Eucharist on the meaning of “is.” That would be you. Indeed, it is I who critique your unwarranted reliance on a single generic verb of being. It is irresponsible translation.
Consider it this way. If I say “I am SR,’ and you say “He is SR,” are there two different verbs of being? Or one verb in two conjugate forms? May I suggest they are just one verb, “to be,” in two forms. May I further submit that the rules of English require those different forms to convey the additional information concerning person, tense, and number.
These are very basic prerequisites to any theological study. Generic verbs like “to be” must have their range of possible meanings narrowed down by the full context in which you find them. Without such a limiting rule, language truly does become Clintonesque; no ordinary reader could ever be sure of what the speaker or writer was saying, because at any moment, a speaker could claim a “magic meaning” that completely subverts the ordinary, contextual reading of the text. It would render the written word utterly useless.
In short, what I’m saying is this. If you’re going to jump into the linguistic pool, you have to play by the ordinary rules of language. Eimi and estin are two different conjugations of exactly the same verb, “to be,” and you’ll need a great deal more information from the context to derive something as complex and obtuse as transubstantiation, contextual information, BTW, which I think you cannot produce from this or any other Biblical text.