Wow, nice research!
All my main drip lines are buried 6-8", and runs the parameter of my yard. Spaghetti lines run to the plants from that main. Sun will absolutely affect the drip line, especially if you have vinyl tubing. Poly tubing will hold up a little better since it has better UV endurance, but I still recommend leaving a minimal amount exposed…
My small shrubs all have a single 1gph, larger shrubs will have 2. My trees have 2gph, and depending on size with have anywhere from 2-8 emitters. I’ve had good luck with the Rain Bird pressure compensating emitters that I’ve used since I bought my house 10 years ago. I haven’t had to replace one yet. Note that the color coding on these is different than what you have. 1gph is black, 2gph is red.
Hard water and deposits can also play a roll in destroying emitters, so if this is a major issue, you can try a cleanable PC emitter, which will still require maintenance, and IMO, if I have to go around and maintain an emitter, I’d rather just throw a new one on there…
All my drip zones are behind pressure reducing filters similar to this. Only time I’ve ever had issues with clogged emitters was if I had a break somewhere in the line and I managed to get some dirt in the line during the repair.
