@Wayne-TP I note the comments from other users. I have four C425s installed, , three of which are outside and have been subjected to fairly heavy wind and rain. No problem at all. I have no idea how long the strength of the magnets will last though, but hopefully will get a few years out of these. 

That being said, the cost of producing a simple screwed base plate with the adjustable ball/socket arrangement that screws into the cameras shouldn't be too much and ought to be (at the very least) included as an item purchasable from the maker. Keeps everything neat and easy (and everyone happy).