How third conditionals differ from subjunctive sentences

YOU are given this sentence, “Franz didn’t take that job he was offered,” and you are asked to assume that you are Franz. How do you construct the statement in the affirmative?

This question was recently posted in my Facebook page by Jakub Res of Brno,Czech Republic. Specifically, he wanted to know how to construct the statement as a third conditional sentence: “Does one have to stick to the past simple, ‘If I had been Franz, I would have taken that job he was offered,’ or does one shift the tenses instead from past simple to past perfect, ‘If I had been Franz, I would have taken that job he had been offered’?”