Rookie QFF question about Economy legs on a J class Reward flight

I want to thank members in advance for any helpful advice to my extreme noob QFF question:

I am exploring booking my first Business class flight using my points. I wish to travel Syd>Paris and return Rome>Syd

The website shows the Syd to HK flight will be in Economy while I will be in J (as desired and available) from HK to Paris. Similarly, there is J availability from Rome to Shanghai but from Shanghai to Sydney that leg will be in Economy.

Why can't my entire journey be in Y? Are there any tips or solutions to avoid making half the trip in Economy?

Not an extreme noob question at all. Suggest you look at all of these factors depending on how flexible you are:

1. Different dates

2. Airlines (consider Emirates options as well as OneWorld)

3. Stop over locations

Also consider flying via Melbourne or Brisbane to increase your options. Flying intra Europe is quite cheap so if you don't specifically need to fly the most direct route to Paris (or from Rome) try another European city and just pay for the positioning flight...

Good luck.

As lost in sing has said, you should look at all your options. Look also at individual sectors by themselves- ie, departing out of Melbourne or Brisbane etc as the QF website won't always give you an option to fly to another city and then onwards (esp if it's on a partner carrier). If all else fails, book the legs separately and change if a J seat becomes available.

Also ensure you book one way to Europe and a separate return from Europe, as if you try to change the return to a J seat once you've started your journey, you won't be able to.