Keep in mind on the bazookas that if the bottom tubes become plugged due to floating leaves and other debris, it will pack up the trap solid. Some people (myself included) made leaf guards to fix this problem. And also you may need to classify smaller then the stock setting depending on your local gravels. I have found a couple places with lots of flat skinny rocks that fit through the stock grizzly, then once inside they turn sideways and act as a false bedrock preventing the gold from sinking into the trap. What that happens the slurry just blows out the top without ever sinking into the trap. This is one reason why I recommend the hardware cloth. The other reason being mentioned above already, which is proper classification is always key to better recovery. No matter where you are mining you should always tune your equipment to the ore you are working. No equipment is one size fits all and works for every situation.
Heres a video where I am using my bazooka with my hardware cloth mod that is being fed 4 mesh material (At about 7:00 minutes). Notice how fast the material is processing. That is about normal flow and what I usually use and it works great.