Roof Rack Recs? (2017 Impreza 5 door)

I recently bought a base model Impreza wagon in Island Blue Pearl (my Bluebaru! <3 ). It has the fixed point attachment things for a roof rack, but no side rails. How difficult is it to install? Is there anything unintuitive that I should be careful about? Are there any extra considerations I should think about because I'm short? I'm thinking of getting Yakima Whispbar crossbars and a cargo box for now, and would like the ability to strap a canoe to the car in the future. Is it better to get the 50" or 60" bars? Is there a Yakima cargo box which is too big for the Impreza? How should I pick? I do a lot of backpacking and will also like the extra cargo space for a cross-country move.

This is my first car and my family's never used roof racks, so this is new to me. Would appreciate your advice!