You need to profile your printer yourself and create your own custom profile based off that.
After that, you need to fix your files' color-space issues.
which I'm trying to do, and have tried many times before with crap results. One spot I always get confused on is ink limits, I never know what to set it at after printing. There's no artifacts or anything like the help docs talk about, it prints from solid color to black. Do I pick the highest point of each section where it turns totally black? Or the lowest?