3mm ID tubes will run into the top of each jacket for the water. The jackets will be connected by short lengths of flexible plastic tube and an inlet and outlet will run from/to the water pump. Compare this with a stock setup with three E3D heat breaks. The black cylinders are the water cooled setup so it's easy to compare.
This will be quite a bit more compact and have the benefit of water cooling. I'll use the press-in Bowden fittings like E3D uses on their hotends. Since I only intend to print PLA and ABS with this hotend, I'll line the entire path with PTFE tubing down to the stainless steel heatbreak. This simplifies fabrication but also minimizes friction.
I'm thinking about mounting options for my Rostock Max or Kossel 250 now. I like the 3 post designs that some of the Rostock users have printer. I think I could do something similar that the heat jackets snap into.