I don't think the image information is so important. PCC does two major steps: 1) plate solve the image, 2) identify stars with color data available and adjust the channels to them. I found 1) fails very often because the solver is not a blind solver. It needs somewhat good start values. If you look closely at the PCC option you will find that the default setting is not to plate solve if the coordinates are in the image. My standard procedure now is this:
- use scripts/image analysis/solve. The resolution of your setup does not change. For the first solve use an estimation, form then on you know it. Position can be searched online or entered (e.g. from a book, stellarium, etc.) The positions in books are Jan 1st, 2000, so select this date. Downloading the star catalogue to the local HD once speeds up the solving process a lot.
- now apply PCC, it won't solve but do the color adjustment only
If the image is difficult to solve solving the extracted L instead may work. scripts/utilities/copy coordinates can be used to transfer the result to the color image.