Does it retract with the wing off? If so, you probably pinched an air line when you put the wing on. I have never used restrictors. I have heard bad things about them. I have just used the needles on my valve. Honestly, I would not even worry about slowing your retraction/extension rate until you are comfortable it is all working well. Nobody is really gonna care, or even see your wheels go up or down anyway. What is import is that they actually work. The restrictors in the lines, are most certainly a failure point, and I personally would avoid those.