I agree with Mike (Deadbodyman)...what you have put on your car needs to come off...It's apparent that you really like this car otherwise you wouldn't have put the hours into it that you have. If you want your work to last you need to get your foundation built....take the car down to bare metal (even the etch primer that you put on it)...I'm surprised... was it the place that mixes paint that recommended "rustoleum" etch? If it was, you may need to find a new paint supplier...swvalcon is also correct, if you can return the grey etch primer...return it.
You asked for directions on the proper way to rebuild your car.
#1) Take the car down to bare metal. Either chemically (stripper...this may not be an option for you because it does give off nasty fumes), or mechanically (sandpaper). Use 80 grit on a DA (Dual Action) orbital. Set the orbital to rotate only, not rotate and vibrate. Keep your paper sharp (change it regularly) and don't spend to much time in one spot. If you do, you'll create heat and could warp a panel.
#2) If you feel that blasting it isn't an option then strip it one piece at a time and put it in Epoxy primer. I have recently tried SPI (test panels only...a local shop was using it and donated some product for me to try) and so far I'm impressed. After years of using PPG's Epoxy, I'm quickly becoming a convert. From what I've seen of the SPI product so far, it is easy to apply, lays down flat and has more than respectable sanding qualities.
After you have the entire car in Epoxy, the body work can begin and that's a whole thread or several threads on it's own.
You mentioned that you had a compressor...what size of tank and how many CFM does your compressor put out. Very often, too small a compressor is used and this brings a whole new gamut of problems.
I hope this helps you get to your next stage.