I'm looking at this flight on ExpertFlyer and I see:

J5 C2 D1 I0 Y1 B0 H0 K0 M0 L0 V0 S0 N0 Q0 O0

Other flights on the same day are also rather full. This is also in the middle of Hong Kong's peak October fair season where flights are really busy.

Given all these factors, I'd say that your chances of waitlist clearance drop from "very good" to "fair, but still likely" given your OW Sapphire status.

If you do choose to issue and waitlist, do let us know the result and how early your waitlist clears.