OP - my advice is to take UA instead of CX.

Weather condition is something we can never change. When it happens, it happens. However, the airline's policy actually impacts how good or bad the flight can be. Specifically, not all airlines deviate the designated flight paths to avoid weather.

Why I would say UA? I frequently fly to the area where typhoons are originated (SFO-HNL-GUM-HKG). Still I was able to enjoy a smooth ride with limited impact by the weather. Also, I took off twice from HKG under severe weather. Despite the wind and rain, they were still relatively smooth.

Although old, I do believe OP you are trying to avoid something like this:

https://globalnews.ca/video/1158700/...pacific-flight

Then I won't take CX.

No one tells you to make it as tight as possible.

Also - even you loose up the seat belt a little, but still buckled up, the seat belt can still give you some protections.