The GL/SSC is just unique enough to be fascinating to me, plus a 12.5” upper was the first AR item I purchased.

But, I think if you want to be close to the original, you only have Options 1, 2, or 5.
Option 1 is cool in its own right and the easiest. I may get one of these eventually. Or not.
Option 2 is apparently/allegedly close to a version of a GL/SSC, but unnecessarily complicated.
Option 5 would be my selection. Personally, I’d probably go with the Forward Controls Design RHF4 11.5” (custom version of Centurion Arms C4) just to keep life simple.