8ga from the panels to controller should work fine
i think you can buy the panels and controller as separate items and come out cheaper, even in Canada
last month i bought (3) 100w windy Nation panels on amazon for $138 each
$448 for 300w
added these to some existing panels on the RV (removed 3 42w panels),
everything is wired parallel, using a PWM controller ( i have used both MPPT and PWM at different times)
definitely cost less to go PWM, and shading will have less effect on the system total
i would stay away from the large panels, high voltage and must use MPPT, which cuts away at the cost savings of the large panel
