I lived in DRW for 10 years & worked both at the airport & as an F/A flying members of Aussie & Kiwi Defence Forces between DRW & DIL.

One factor to consider is if travelling between October & March it's the wet season so there can be a lot of thunderstorms at that time which can cause flight delays.

International & domestic flights operate from the same terminal so on exiting customs turn right & hsad down to QF checkin. Baggage close off is 30 minutes prior to departure. If travelling HLO you could do OLCI 24 hours prior then bypass & after customs head tbrough security up the escalators to the departure gates.

As the a/c operating your DIL/DRW flight will originate in DRW you'll be able to monitor the progress of the outbound flight to sed if it's running on time.

DRW Airport should be fairly quiet at that time of night for international arrivals so you should get through customs reasonably quickly.