Looks like it has enough paint that you could get a clear to stick
have not tried the rust killer approach on exterior panels, but everything I have done with rust killer has turned the rust to black and then that is what you get. So unsure if that is the look you would be after
The Chev I hit with the scotch pad with a diluted CLR mix. Objective was to clean up the paint oxidisation and rust streaks. There is one door I didnt do - you'll have to check it out at wagnats. The roof was mainly surface rust so did the same, but it really needs something to protect it
The Buick was heavily patina'd. I did scotch pad with a diluted CLR mix and coated it with Carboline RIPO oil. Soaks in to the non paint sections, brings out the depth of the colour (and adds a bit of gloss) and most of all makes the water bead. I'm sure I'll be due to do it again. I have some in stock if you want to try it out.
KE26 I used Morris Ankor wax - it never quite tacks off soo gathers lots of dust and finger prints. Would like to take it all off and try the RIPO oil
I'll have to get some pics