Don't know if I've missed it, but has the OP considered switching brakes to Long Drop DPs? I've done this successfully on a couple of my touring bikes due to the inefficient cantilevers supplied as original equipment. I don't run tyres wider than 32c though.
No need, very happy with the stopping power of the new Shimano CX50 cantis with Swissstop Flash Pro BXP pads (the Shimano BL-R400 levers probably also help)
