I've had better luck with Tri-Tec 14 than with any other brand of fly spray. I apply it before every ride (I ride daily) out of habit, but it isn't necessary to use it that often in my experience, although it doesn't last quite 14 days as advertised. Ha Tri-Tec smells great and creates a nice shine. It also has sunblock in it to protect from UV rays and coat fading. Tri-Tec is effective because of the level of Pyrethrins/oids in it (0.35%)-- 0.20% Pyrethrin and 0.15% Cypermethrin, which are an insecticide and insect repellent.. Bronco has 0.15% Pyrethrins/oids. Pyranha, another popular fly spray, has 0.10% Pyrethrins in the Spray N Wipe, and 0.30% in the aerosol version. I pay $15 per bottle of Tri-Tec 14 at a local tackshop and its worth every penny.
Info on Pyrethrins and Pyrethroids-- http://npic.orst.edu/factsheets/pyrethrins.pdf
I'm not really sure where you could get it in Canada, but I'd just look around any tack shops or farm stores you have there. I know you can get it online if that's possible for you..?