Hey 67Fish383S,
I've gone through this a number of times. May not be what you want to hear but I found the best way to access the nuts was to remove the header panel completely. Depending on how corroded and rusted the nuts are you might get away with penetrating fluid but its useless if the nuts are spinning. I put the header panel upside down on my bench and then used a dremel tool with a cutting disk to slice the nuts in half. This method is way less time consuming, not near as frustrating and worked great!