Ben,
Had the same experience as you. After a week of penetrating oil front and rear on the cage nuts( I had the front wings off), they still wouldn't budge (like the seat tracks).
I should mention that I was able to remove the doors as I could get the fasteners off the door hinge side. I left the hinges on the car until I could get them off....
I used heat and an impact driver/bfh to get them off.
Cheers,
M. Pied Lourd