For the 6g72 guys out there, what have you found to be the easiest way of getting the rear exhaust manifold off?

considering this diagram:
...1.....2.....3
4.....5.....6.....7
I already have removed the #1,4,5,6 nuts. I currently have a 1/4 drive stuck on the #7 nut and cannot get it off after trying for an hour or two. will keep working on that tomorrow (started to get really rainy and windy).

tomorrow I will also try to drill out the bolt holding the heat shield on, that may help with the #2,3 bolts because I cant even see them right now.



Am I overthinking this or is there something I haven't tried? I will be attempting 2 and 3 from the top, and 7 from the bottom again.