I did not like the idea of their fabric yoke for the same reason you didn’t.  I did not know of any manufactured yoke that would clamp to those gunnels.  Some of the yoke pad combinations that were suggested to me were about 20% the weight of the canoe. 
My first yoke broke just as I was starting the south Cache Lake portage so I had to use the pads that came with the canoe.  By the time I finished the North Cache Lake portage both sholders and both hips were black and blue.