I am a sprinkler contractor and read your comment. I am trying to understand why you need the stainless steel even with the sand issue. Is it going to perform better? It sure will cost more. I may need educating in this area.
My Idea is to use a Rainbird 1812 or Hunter Pro Series 12", or go with the 6" popups. Plastic is good in the world of sprinklers.
Dan Todd