I would not recommend buying Aeroplan miles - read on one of the travel blogs that their program is very glitchy at the moment (sounded a bit like LM) and there's a devaluation coming as AC re-integrates Aeroplan (which was a separate company) + AC charges crazy surcharges on it's own metal and a few other *A partners. Finally those Aeroplan prices do not include Canadian sales tax (which could be as high at 17% - not sure about miles). Anyway
@MEL_Traveller I'm sure you're across all of these considerations - but maybe others aren't.
(I follow AC and Aeroplan quite closely as I have used LM often for AC bookings and/or bought paid tickets on AC).