Your numbers are super off hah. A Graco mark 5 costs $6,649 USD alone.Alpa is about $11,000 usd Just bought the continous flow for $14,000 usd. I believe you about the boxes not much reason to have normal size boxes when you don't need to fill up manually and having bigger box let's you run longer.I have no clue what the sock is for the hose. I've never had much of an issue with keeping it clean, and the kinking is easy to deal with by having a z-swivel installed.
I own both Apla tech and ames continuous flow. The slimline boxes from Apla and the handles from Apla tech are superior to ames in my opinion. Apla tech is $8500 with a Graco Mark V, Ames is $18,500. If anyone needs any comparison info between the two systems, I can help you out