Ok, I bought those exact fittings for my setup. Not matter how hard I tried, I couldn't get those fittings on the stock plastic piece. I didn't want to try too hard and break it.
And when I was first doing my build, I was advised from a fellow friend that braided lines are a pain in the ass and if he would have done it all over, he would have used push-loc hose.
I know you like the look of the braided line but it's just my opinion.
This was his braided line setup.
This is from the Fueling FAQ.
Scroll down about 7/8ths the way down, you'll see pictures of One-Eight-GTIs setup. He uses those fittings. No clue how he got it on without breaking it but apparently he did.