Again, I think the answer is somewhere in between.
There has to be a mild tension exhibited in the body, where the connections are "flowing" together, but at the same time you can "increase" the pressure in certain areas.
Which means you can "store" and keep it "flowing" at the same time
Blockage means you're keeping something "tense" by clenching the muscles or you're simply disconnected from the rest of the points. If the muscles around a joint are tense, you can't connect them to the rest of the body, cuz the tension being derived is an "individual" tension being generated by local muscles.
Which is why most arts emphasize "opening" the joints to let "ki" flow through them.
About the center of gravity, its not that important, what's more important is the overall connectivity between certain key points if you ask me.