At first sight it is surprising for me to treat subjectivism as epistemological foundation and not the other way around: analyse the epistemological basis of subjectivism in a Christian educational context. Nevertheless, it is really difficult to respond to your question without having more details about it and certainly more knowledge.
I think the best for you would be to ask for suggestions to professors in Philosophy or Theology, either at your university or at any other place. I did that when I was doing my master thesis and was stuck with a difficult concept; I wrote to a professor in another university, who had published a book in a related topic, presenting my ideas and doubts and asking for his suggestions. I t was really helpful.