You picked the Caspian bushing, which is the thickest one. I thought you did that on purpose... some people like the look of it, as it insets the outer barrel, or gives it a flush mount (depending on the barrel).
If you want it flush with the spring plug, you'll need either a Government style bushing or the Series 70 style.
In any case, it looks good.
Don't know what that little square bit is... if you take a picture of it, I might be able to identify it.