I understand body filler to be very porous. Exit mentioned that he had filler w/ NO primer and it sucked up the paint and made a little patch that differed from the rest of the car.

I don't know about glaze, but from my understanding, filler needs to be top coated w/ primer. I've heard it mentioned before that Evercoat glaze doesn't necessarily need a primer, but scratches might swell. A sealer is another alternative.

I've used rattle can primer over scuffed paint on a perfect panel in the past, and it failed miserably. If it isn't 2k, I feel confident the paint will knick off when a rock hits it regardless of how hard the paint is, since it's an adhesion issue. It might have worked better if I didn't use rattle can primer at all and just painted straight over scuffed paint.

Hope this made sense.