Another thing to consider is what's required to drop the tranny. It may be that you have to drop the exhaust in order to have enough clearance - hard to tell from photos. I'm not saying anything is wrong with what you're doing, just pointing out that at some point down the road you might have a need to drop it, and having to chop the exhaust into pieces and then weld it back together would be one of those added frustrations that make the problem grow. Better to think about it while it's going together.

Also, from the earlier pictures I assumed that your X pipe was all one piece, not a short X with extensions. Messing with the extensions one at a time makes it a lot easier, IMO. You can set the X where you want it, and form individual pipes to fit.