Are you sure it is sound to use John Donne's eucharist poem in a hymn? It seems he rejected the dogma of transubstantiation very clearly, as the quotations on pp. 27-28 of this book show:
https://books.google.com/books?id=Q6MFyTqy0DwC&lpg=PA28&ots=o0FBs6Q4HO&dq=john donne transubstantiation&pg=PA28#v=onepage&q=john donne transubstantiation&f=false
His poem isn't an affirmation of the Catholic doctrine, but a dismissal of it, as if to say only: whatever Jesus meant by His words at the Last Supper is fine with me.
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