I think the ratio changes as you get more advanced in the language.  As a new beginner, obviously, you are spending a lot of time learning completely new things, like words you have never heard of and grammar concepts that are completely new.  Even beginners need to review and practice what they learn.  The more advanced you get, the learning feels more like practicing--- you are not learning so many completely new things, you are not seeing so many words that you do not think you ever heard before, you are just learning them more thoroughly and becoming able to process the language more rapidly and more competently.  

It's kind of difficult to quantify this type of knowledge learning. I am more in tune with the 10,000 hours of learning/ practice paradigm. However,, if the “20% learning : 80% practicing，”  method works for you, go for it! Different strokes for different folks.