Depends on what area in Canada the apiary is located. Yes it can get plenty windy. I see the picture in deep wood, sheltered. And with poles to stabilize them.
The achievable size of the hive is also area dependent. When conditions are good, the genetics are good, and the hive is healthy and well managed by the beekeeper; a single queen hive easily achieves six to eight deeps tall.
There is no -need-to double queen. It is just another tool in the beekeepers toolbox. for goals such as;
- used in the spring to boost the rapidity of population buildup in the 6 weeks before a very short monocrop flow.
- to help small/weak colonies to get over critical threshold in a much shorter timeline.
- to requeen a hive with an old slow queen, easentially a beekeeper-made supercedure.
The multiqueen configuration is always short term, with specific purpose, and never permanent. As mentioned before, know why you want to to it, how you will go about it, and when are start and end times of the window to do it.
Some folks will mistakenly look to multiqueen to improve a colony that is slow, nonproductive for reasons of poor genetics, old or defective queens, unhealthy hive conditions (poor comb, pests, disease, virus etc)
Hope that helps