I would start with something like the Watercolor Paper Radiant White setting on the Epson----I'm just not familiar with Canon printers/drivers. On the Epson printer driver, users can also also decrease ink under the configuration menu. I just noticed that for Phototex, I have this set at -3. Thankfully Qimage keeps track of all these settings and the icc profiles for me! If you are playing around with the ink settings in the configuration menu (assuming Canon is similar), if you are generating your own icc profiles, you should be using the same settings when generating the color targets.
ken