How can you tell enough oil is getting up top
 

during loaded continuous duty? By the time the valve cover is off it is hard to tell how much was getting up there to cool the springs adequately.

There are some experienced tuners/builders here who must have a great system??

Clatter noise is the first clue. Also, I never use restrictor plugs in my roller motors. The manufacturers say the trunions on the roller rockers dont require as much oil as the pivot ball systems. I say the oil supply that the designers engineered to run to the valve train shouldnt be tampered with regardless of what kind of hardware you have up there.

I believe someone is now offering valve covers with removable, clear lexan cover plates on top of them.