The trick is to find 3 empty stations in a row and take the middle one. If you can manage that then you're all good.
Only problem being, that in the Toronto area, all the frequencies are assigned, have been for a few years now.
I find the FM transmiters work fairly well outside the city.
They really are very dependant on the radio you are using and the antenna, one person's success may not yield the same for you, so your best searching for one on your own