I would suggest the era of quick commands is now over. KA have around 40 pilots waiting for command courses who have already passed PCA. Anybody joining today will probably have to wait 7-8 years for a command as many of us had to. Lots of cadets with the hours for command now and of course the majority have no plans to eventually leave Hong Kong like the expats. No commands this year so far and just two vacancies advertised recently on the 330 which will either go to senior 320 Captains or senior 320/330 FOs should they decide to bid.
Be very careful about joining on COS18 is all I would say. Without a quick command it probably won't be worth it unless you are single, no kids and have no plans to change that situation.
Take home for a Year 1 FO on COS18? Nobody really knows as we are all either Expat B or Standard Contract so no point in giving you those figures as you will almost certainly be earning less than anybody already here. I wouldn't recommend COS18 to ANYBODY. Hong Kong is extremely expensive. In my personal opinion it isn't worth coming here anymore, unless you just want the rating and plan to move on after 500-1000 hours.