There are two methods of becoming a reserve pilot: become a regular force pilot, rotary- or seized-wing, and CT, or apply for HELICOP (HELicopter Industry CO-operation Programme). For the latter, you will need a commercial helicopter licence, 500 hours minimum with a fair amount of that turbine time, and possibly an instrument rating. I cannot remember if that's necessary or not as we haven't had enrolled a HELICOP guy in Borden ever - we got the last two near the end of our Downsview days, ie thirteen to fifteen years ago.
Not a raving success, that programme. It was dreamed up by the same guy who shut down the Reserve Pilot Training Plan, which, by contrast, gave us three to four new pilots annually.