nice work there, Greg. I learned, as you have, to use the various fittings and pieces to be found in the Irrigation section at Home Depot, and other hardware stores. Between various hardware stores, and auto parts stores, I can usually find what's needed. After playing with these parts awhile, you realize that there are many ways to do hose or tubing connections.
One thing that has always surprised me, is when I've been in someone's auto repair shop, they never seem to have much in the way of bulk hose, caps, or fittings. But then, most shops and mechanics spend their time just fixing/replacing existing parts, not doing custom stuff like we are here.
You have touched on the idea of improving/changing the flow potential in a hose system. This is actually advanced thinking, most would never even consider the concept!
By varying the diameters, lengths, and even angles of hoses/tubing, you can alter flow dynamics. Like, say, in the crankcase vent system, if you want to remove liquids/vapors in the gas flow, you increase ID's and lengths of the hose. This slows the gas flow rate, and increases dwell time within the hose. This then promotes condensation of the vapors in the gas flow, helping the entrained vapors to drop out of gas suspension. Adding a catch can or oil separator to "tuned" hoses will remove much of the water/oil content in the crankcase vapors, and keep the engine cleaner inside.
Tracy G