I used the 3M self leveling sealerWhich brand of self levelling did you use?
Is your headliner in? If not you'll want to spray some Eastwood type rust paint inside the top as well since the rust will have travelled there through the seam.
You think it's OK to paint over the coatings you mentioned? Or is the idea to get it into the seem then clean the outside of the seam and then paint?Atf won't dry up for a while, a long while, but most importantly it'll wick into the pinch weld and stay there, to help prevent rust.
Fluid film, cavity coater, atf/kerosene are the best choices. Imo put that stuff in there after rust converting, prior to paint. Don't want the paint sealing off any areas that the corrosion inhibitor could get into.
^ This. You can paint over seam sealer, but not ATF/cavity coater/fluid film. I mean you could, but the paint wouldn't stick.You won't be able to paint over rust inhibitor -- it is an oil. Once it goes on, no paint is ever going on it again because you won't be able to clean it out.