Primer Sealer and Red Oxide question

I had a debate when I was a bodyman about coverage over Red oxide primer. I took a junk panel primed half Gray and half red oxide. Sanded painted 5 coats of color and cleared. When in the light you could see the color difference. My Charger Red Dart I painted really popped. I sealed in white before paint. I think you are correct to tint and or seal the car 1st. JMO
If it's the rim color (Nice) I would seal White,light gray or tinted.