Couple of things;

- I used to be a proponent of the small castration rings but feel they actually cause leaks instead of preventing them. YMMV. Plus they fairly quickly deteriorate by design.

- I like the "Wings and Wheels" tubing color coding scheme. Helps to prevents errors and makes seeing which tube goes to what much easier.

- All this info and more is in this presentation.
http://aviation.derosaweb.net/presentations/#airlines

Enjoy!