There are at least two companies making these glasses - Champion and Knobloch. They are close in price and features. There are Canadian dealers but you'll have to poke around the competitive shooting market to find out who.
I have a third lens - one for prone sighting, one for the spotting scope and a third to look around or watch the flags. It is aligned like a normal lens for my right eye. Everything adjusts with a fine Allen key. Mine have a screw up/down bridge, and spring wire eyepieces. I also got a detachable cone fitting to better centre the sighting lens in its optical centre. Get the hard case because these are a lifetime purchase.
My optomitist kept calling it an appliance when I explained what I needed. I told him it was to focus at infinity and then add a margin more correction for acuity. He had fun submitting a claim for glasses with 3 lenses.