This is only conjecture, but if you follow the theory of using the Spalding Manuscript to create the Book of Mormon then trying to sell it in Canada makes sense. In Sidney Ridgon's and JS's minds, taking it outside of the US would eliminate alot of legal problems. JS, OC and MH may have thought that if they tried to publish it here could cause some problems because of people who knew Spaulding personally-leading to legal problems for plagerism and stealing intellectual property. But if could have been published in Canada then it is outside the jurisdiction of the US legal system and the out of the knowledge of Spaulding's family.