Given what has happened this week, I wouldn't be surprised by news of Saudi applying to join SCO, but I haven't seen it anywhere yet
If Saudis join SCO, then they are willing to be on the record that they are in the China camp. Then, I think Petroyuan is a foregone conclusion.
well, this just happened:
RIYADH (Reuters) - Saudi Arabia’s cabinet approved on Wednesday a decision to join the Shanghai Cooperation Organization, as Riyadh builds a long-term partnership with China despite U.S. security concerns.
Saudi Arabia has approved a memorandum on granting the kingdom the status of a dialogue partner in the Shanghai Cooperation Organization (SCO), state news agency SPA said.
Joining the SCO was discussed during a visit by Chinese President Xi Jinping to Saudi Arabia last December, sources have told Reuters.
Dialogue partner status will be a first step within the organisation before granting the kingdom full membership in the mid-term, they said.