A friend just shot some Omni (ppg) on a mid-80's dodge pickup. Its a factory red truck. PPG base was 600, the Omni was 100.

He said he took other red paints left over from previous jobs and applied a base before applying the final coats of the correct paint.

Meaning, it will take several coats of the cheaper hues to cover.

You should probably add color to your sealer before painting the final coats of color.