With the opening of the cadetship to international applicants, you could imagine they'd just get flooded with a gazillion applications, so processing all those prospect cadets is not a short or quick process. 6 months seems to be about the norm, but its not unusual to wait upto nearly a year aswell. Some lucky people do managed to get called slightly earlier. HK probably will give you a better chance of getting an interview earlier, how much earlier? who knows, that and you will also have to be prepared to fork out for your plane ticket there for the first interview.
it really is just a matter of applying, then sitting and waiting patitently, in the mean time, take it as an opportunity to prepare.
Superjet, don't worry, 4 months is nothing! it can take upto a year before hearing anything back although its normally 6-12 months going by most folks experience on here.