[CC69Rat]

I would:

* Sand the repair area with ~80 grit on a DA, down to bare metal.
* Do the repair work and hammer / dolly out as much of it as you can. With as minimal filler as you possibly can, right on the bare metal.
* Block the filler as best you can to get it as flat as possible (I use 120 on a DuraBlock)
Epoxy prime ( I use DPLF - PPG ) the bare metal. Epoxy needs to cure for 24hrs. Do not allow to sit in DPLF for more than 7 days. 2-3 light / medium coats
* Scuff the DPLF ( I use red scothbrite )
* 2-3 Coats of high build primer SPI / Omni / PPG depending on your preference
* block with 220 - DuraBlock ( should begin to get 'slick' at this stage )
* re-prime with high build - 2-3 light coats being careful not to build too quickly. Let each coat flash / cure before the next.
* guide coat and block again with 400

Depending on the color you choose and metallic or non-metallic you might need to consider blocking to 500/600 to hold down on sanding scratches. Metallics will fall back in 400 sand scratches.

Seal, base, clear ..