FYI, CX has an excellent page to show your allowance when flying CX. If you choose J fare and compare the allowance of CX gold vs other sapphire, you can see CX Gold are entitled to 3 pieces while other sapphires only got 2 pieces, which is matching the alliance policy that grant no additional allowance in this case.

https://www.cathaypacific.com/cx/en_US/baggage.html