My curiosity got the better of me about whether flights of YTM operated IFR or VFR, so I looked at FlightAware track log of YTM for the cruising altitude of some recent flights.
It's a little tricky without knowing for the QNH for the particular day, but i see a lot of flights were VFR to/from YPLC between 4500' and 7500'. The track log for Wed June 21 (YMBD-YPLC) show some unusual groundspeed (not airspeed) fluctuations on climb from 4000' to 6500' (113 - 54 Kts) that may be caused by a downdraft from westerly winds over the Adelaide Hills, but the subsequent cruising groundspeed suggests a fairly light headwind. Nothing else looked out of the ordinary, although I'd fly as high as possible over water (just in case) to have maximum glide range.