robert schlatte

I have a 1980 Schwinn Voyageur 11.8 that I have upgraded and use for loaded touring (see pics). The original brakes are Dia Compe single pivot calipers. They have worked okay but now I am considering installing Tektro R539 dual pivot calipers. The bike does not have cantilever bosses so that eliminates cantis as an option. Would installing dual pivots be a better option than the single pivot brakes to increase braking under heavy load or should I leave well enough alone. I have read a lot of threads here and have not found an adequate answer, but I would certainly like to hear experience opinions.