All depends. My old 42dd downpipe only required 1 spacer right after the cat. When I had to replace the down pipe due to corrosion, my new one required 2 spacers. 1 pre-cat and 1 post cat. So you may need to put 2 on there, but you could just start with the 1 post cat (or in your case, where the cat should be).
It's a crap shoot. There are so many variables that can affect it, you just have to keep trying different combinations until you get it to work. My advice is if you don't have a VCDS cable, buy one or borrow one as forcing the readiness tests is much faster than driving around to see if your CEL pops.
