Regarding item 4. Tubing is this valid:

"More recently people, including myself, have switched to 7/16" ID Masterkleer tubing which can be purchased from www.Mcmaster.com. Check out my stores guide for the exact part number. The reason for the switch is that it is considerably smalller than 1/2" ID Tubing (the outer diameter is 5/8" compared to 3/4"), gives a tighter fit on hose barbs, and does not loose any performance compared to 1/2" because of the smoother transition between barb and tube." - MaxxxRacer


And if so can you use those 7/16" ID tubing with your existing 1/2" fittings?