I can't picture your layout exactly....
but yeah, I had a custom extension made by a local muffler shop.
The issue was the smallest diameter pipe they had was too big to do what I wanted to do, so
I used the adapter bushings that came with the genturi. They bent a short piece, approx 12 inches long, to approx a 45 degree angle, welded the bushings into one end. Expanded the other end
I took it home and drilled holes through each end so I could use a hitch pin bought from tractor supply to hold things in place....but the hitch pins aren't really needed.