Is there an optimal height for sealed vapour barrier on piers in an encapsulated crawl? (This crawlspace does not have a direct capillary break between concrete and wood members.) 

Also, on the rigid foam exterior walls of the crawlspace, should I run up the wall with vapour barrier as high as the floor assembly? 

This property is in Southern Ontario with a wildly varied climate. From -25 degree Celsius ice storms in the winter to +35 degree Celsius days with high humidity in the summer.