Look, you don’t even know the terminology you are writing about.
Transubstantiation refers solely to the explanation of how real presence comes to be.
No one, no one with a half a brain about historical theology is looking for transsubstantiation in the Church Fathers.
The issue is whether Christ is really present or not.
You are using transubstantiation as a synonym for real presence. It is not. Luther believed in real presence but thought it came about by consubstantiation.
Ignorant Catholics may use the term transsubstantiation when they mean real presence. Knowledgable Catholics do not.
I’m giving you a hand up. You could be better informed than some ignorant Catholics.
Schaff’s argumentation is fallacious, weasely. He uses terms equivocally. He’s playing games. I’ll give you a piece of advice: if you want to argue for a Reformed Eucharistic “spiritual” presence, use someone intelligent, like Heron. Schaff does you no credit.
Discuss the issues all you wanta, but do not make it personal.