Is there a way of working out approximately how much money Zacchaeus would have given away and given back as restitution?

Luke 19:1-10 relates Zacchaeus’s transformative encounter with Jesus, which had the chief tax collector almost instantly promising to give half of his possessions to the poor, and paying back four-fold anyone he had cheated. In a sermon about that yesterday, it was said that often the last thing to be converted is a man’s wallet, but with Zacchaeus, it was the first thing to be converted! Given his wealthy status, what might half of his goods amount to, in cash term value, and roughly how much money could he have committed himself to repay to those he had cheated? Can this find a basis in traditional taxation systems of the Roman Empire back then? I'm assuming Zacchaeus, the 'chief' tax officer, was in charge of a group of other tax agents who had to give him their collections so that he pay Rome the annual amount it demanded, leaving the rest as his wages, so the more dishonest he was, the richer he would become.