Some of the following is specific to the US, but may be relevant for BC as well:
12V nominal (17V MP) panels are limited to about 135 watts but can be shipped by UPS. Amazon is a great source for these under the Renogy brand. 24V (34V MP) panels are usually 200 watts or greater and because of their size, cannot be shipped by UPS, only motor freight. When the freight is added in, 12V panels are often cheaper if the total wattage is a few hundred. For example a 150 watt 12V panel from Amazon is $1.37 per watt, whereas 200 watt panels are about $1.00 per watt, but shipping is more than $50.
Some 12V panels, like Kyocera's, have blocking diodes that will let it continue to operate in partial shade. I don't think that this is true for 24V panels as these are produced for the mass power installations where there is no shade.
You can buy the 24V panels from an online retailer, but not Amazon as they are geared towards UPS shipments. Google online solar panels and you will find dozens.
Even though the Chinese dominate the world market in panels and their panels are as good as anyone's, the same can't be said for their controllers. Buy a US (well US designed at least) controller from Morningstar, Blue Sky, Outback, etc. They cost several times as much but won't fail as much. Amazon is as good a source as anyone for controllers.
There are two critical parameters for controller selection: the maximum input voltage that it can handle which is dependent on your panels. Virtually all MPPT controllers can handle the Voc of a 24V panel. The other is the output current. Take the wattage of your panels and divide by 12 to get the maximum current you are likely to produce. I would add a safety factor of 10-15% to this value.
Wire the panels for a 3% voltage drop from the panel to the controller and the same for the run from the controller to the battery which will have to be a size or two larger if you are using 24V panels. Fuse the battery connection. You don't need to fuse the run from the controller to the panels because the panels themselves have a finite current capability which the wire can handle. You can wire directly to the main DC breaker on your DC panel if it is more convenient than to the batteries.
David