For registration issues clean the main belt the platen rides on, use a solvent like barsol, just to make sure it does not damage the belt, then rub pure eucalyptus oil on it. The platens seem to stay put better after doing this.
You can also print a CMYK box on a dark shirt to test your settings in the RipPro SW.
set them all to -1, run a small test print, 3-4 inches with a white layer, then if the color & white do not line up, adjust your"ink choke" settings in increments of 5-10.
You can set at the following: T-10, B-5, L-10, R-10...registration is almost perfect most of the time, You can also get updated chips that go on the main board (behind the control panel), ask your distributor about them, you can see the numbers on them & they can tell you if you have the old chips or new chips....Hope this helps...