Wouldn't simply modifying the save game file to add iron as a trade good to Judea work as well? Then you don't need to fiddle with the effects of
trade goods as such.
Then again, getting the right trade goods as a small state is half the challenge! Especially when no-one wants to trade with you because of religious and cultural
differences (THAT is an annoying feature which I would like to see modded, btw! OK if Greek states do not want to ally with my Baal-worshipping Carthaginians, but
not even a trade route?). But why not beat up another small OPM which happens to have iron as a trade good?