OK took the turbo out. Like everyone said, and I tried anyway, but the stud keeps you from letting the turbo drop. I had to remove the exhaust manifold to get the turbo out. Better that way anyway as I'm also replacing the oil drain gasket at the turbo.
It's an aftermarket hitech and it does have two chambers as does the manifold.
The fellow that installed my turbo way back when used a pair of asbestos style gaskets... . not steel. And they look to have only had the single hole. Lasted probably 75,000 miles.
I don't see why using the square one matters. Having a minute gap between the two chambers shouldn't be a problem would it. Love to get the job done today otherwise I'm on hold for parts.