I came to this thread expecting to see 35 mins on separate tix.

This isnt risky!

Absolute no brainer. Low risk. Do it. Yes of course if your ex-SYD leg is 2+ hours delayed you may misconnect, but it's rare.

Otherwise, there's no better major airport in the world than HKIA for such a thing. For perspective I regularly connect CX to CX at HKG, my last 60 minute gate arrival to next departure connection, I spent 20 minutes in the lounge. (I also prefer to board last; CX gate closes 10 mins before departure, key to note). 2 hours is an eternity in HKIA connecting.

To help your case or if you're nervous, check in online for your second flight and have your BP ready so you neednt visit the transit desk. (Although this is pretty fast also if needed ) If for some reason you land from flight one with 35 minutes to spare, flag the people who will be standing at the jet bridge and ensure they know you've got a connecting flight (just on separate tix). They'll escort you thru transit and are in touch via their cellphones with whoever at CX holds flights for transit pax. I've had a few close calls but *never* missed a flight just due to dumb luck of a bad transit (I've had flights leave without me but it was known in advance and we were hours delayed, I was met at jetbrdge with my alternative).

Absolutely not an issue at all. Good luck (but you won't need it!!!)