I have two gaskets on my mainfold for the following reason:

A few years back, I had the manifold resurfaced to eliminate some warpage.
I reinstalled it with one gasket. Problem was, the locating rings (spacers?) that insert between the intake ports and the intake manifold were not machined like the manifold. What happened was that those spacers held the manifold just slightly away from the gasket. It was fine while it was cold, but after it came up to temp. it would not seal and caused a high idle and miss at high speed. Took a while (and a lot of carb. cleaner!) to diagnose that problem - never even thought of it at the time. A real duh moment after I realized what was wrong.

Anyway, it was easier to just add another gasket than to grind down the spacers. It has worked fine ever since. Yea, I know it is not factory, but there haven't been any ill effects. I'd suggest you measure carefully the depth of the recess in the head and manifold and compare that to the length of the locating rings.

I'd also just cut off that spinning stud and either heli-coil it or tap it larger (heli-coil preferred). It's much easier after it's out.

Also, I've always been able to access the nuts under the runners with a 1/2" box wrench. Can't remember it ever being difficult.