A second bottle to catch any yeast water that escapes is a good idea. The yeast can really make a tank nasty. It also lets you see how many bubbles the yeast is making so you know when it starts to slow down. Remember to change it out every two weeks or you will end up with an algae outbreak. I learned that the hard way.
I tried every diy diffusion method and finally just drilled a hole in the intake pipe of my filter and glued the CO2
line into it. That way my filters impeller chops up the bubbles and distributes it through the tank. Some say this eventually destroys the impeller but I have been doing it that way for a year with no problems.