Joyride all the way. When pulling the tube, once the mouth gets past the elastic band, put your thumb over the opening.
I never put my tubes back in the harness. All that does is take time to put them back, and more time trying to differentiate which tube is full, and which is empty. I stuff empties into my cargo pockets, or down the front of my shirt (the harness keeps the tube from dropping out the bottom. A dump pouch would work too. That way all I have to do is reach behind me and the first tube I feel, I know is good to go.