[skunkwerks]

Just my FYI from many years of learning from complete paint jobs and paint repairs.

Self etching primer in spray cans is ok at best for small projects up to wheel size.

Car bodies and convertible top frames and big sheet metal panels need the two part formula from the paint store and sprayed with a gun.
This must always be covered with a 2 part epoxy primer such as DP-90 or the like.
Then you would scuff the DP and apply high build primer.

Anything in a spray can will give you limited results and adhesion problems.

Just my 2 cents.