[MP&C]

You may want to check the instructions of the panel bond, but most require bare, prepped steel. Part two of your question, not much of anything sticks to POR15. Part three, the rocker areas tend to become a collection point for condensation that occurs on the inside of the roof. The water runs down the A and B pillars and deposits inside the rockers. Any overlapping is sure to be another collection point for water and where you’ll find the next rust-through to occur.

The best way to fix a rocker is to replace it in its entirety and spot weld as the factory did to minimize weld distortion.