Still TBD on the killer... need to do some research to update my knowledge. In the past I have used RustMort but that isn't necessarily going to be my choice this time. I figure I am going to buy a gallon and put it in a garden sprayer.... after doing a through job of cleaning the car (compressed air, vacuum, high pressure water and then dry with heat/fans/dehumidifiers) I will spray it down in a small area to test, then if it works as anticipated will do the rest of the car to stop what rust is present for now.
I probably should start a 'build' thread and take this conversation over there so we are staying in the forum rules/guides. Will post a link here as soon as I do that and will make updates there as things progress.