We can do this without sending gpt to the Greeks and losing our ability to attack them for twenty turns. First we trade for PP, of course, sending away gpt and possibly our third source of furs. Then we get whatever gold we need to top up the deal with the Greeks by buying it for gpt from the wealthy French. The harder question is, should we make the purchase of PP from some nation with which we aren't really involved yet, or from the Japanese, so that we'll get a windfall if they sneak-attack us? Since the Japanese are broke and the 200 gpt or so would help them too much, I'd choose a neutral trading partner, but it could be argued either way. If there's any chance of getting two of the Greeks' techs for PP, Sacred Art is the one we don't want.