Rust converter

I am in the process of removing the factory undercoating on my 73 Duster. My plan is to hit it with Rustoleum or something similar then use Raptor liner as the new undercoating. I have searched on this site for suggestions on a product to use but haven't made a final decision so if anyone wants to help with that great. My question is on prep. Everything I have read on here says there must be some rust present for those products to work. I have basically gone down to bare metal. I don't want to have to do this again down the road because of a failure now. Any help? Before, during and after pics.
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