China should make it a priority to buy oil and gas from Saudi with Yuan. If China could make that happen, couple with opening the capital market in China for Saudi and other resource rich nations like Russia, UAE etc, then Yuan will really take off. China should also establish commodity exchange that allow foreign traders participations with Yuan as the official currency. Once every thing in place, the demand for Yuan will skyrocket.

Opening capital market to Saudi and others will benefit both sides. China will not need western banks' investment anymore, while Saudi and others can diversify their investment away from sanction proned US banks. After what happened with Russia, it won't be hard to persuade Saudi and others to diversify their investments.

The problem is whether China is ready to let go some of the capital control.