if you get a bed run(mix size) or full size they will prob start breeding right away. make sure there's always some food in there, they eat slow, but they dont really stop eating especially for a large amount that stock together.
they will be sexually mature in about 2 month after hatch. to tell they are ready, they will have a band around their body at about 1/4 of it's body length. it's really easy to see. try to feed off on those without first so they can kept producing for you
3 month is a average time that population double it's amount(without taking out from the bin), which means if you dont feed off from the bin you 250 worm become 500 in about 3 month( might vary cuz the condition)
I never try canadain one, cant give you much tip other than they are huge at full size(very good for fishing) and they should be kept at lower temp below 60(they die if it goes above 65, which's really hard too keep in so cal). most place that carry them keep them in frige.