I have been doing "img split" for years on topo maps that I can only download as an "img" file and not as a install version.I tried using GMapTool and cgpsmapper to split the .img file with the option Create for Mapsource and then I installed it. The result in Basecamp, however, was simply horrible and the map was not useable.
Once you have it installed on Mapsource , Basecamp or GSAK you can pick the tiles you need and compile a "img" file to your needs and install it on your GPS.
Please give more details as to
Post some screen shots of what you are talking about.simply horrible and the map was not useable
Plus I gave you a link to a smaller version of the topo canada from a different link did you try that "img" file on your GPS???