There is no such thing as a sluce box that will catch gold. All any of them will catch is visible gold, 100 mesh up! The water flow is too fast to hold the micro gold. Since that visible gold is only about 5% of the total gold your running, the absolute best sluce looses 95% of the gold ran through it. This includes all high bankers, and dredges that use a sluce system. Sorry but that is the truth. In fact, you run a 4 inch dredge all day, you will dump enough fine and micro-fine gold back into the creek to pay for it several times over!!!!!
Learn to use your gold pan! Quit being afraid of it! A supersluce pan will hang on to 95% of the gold! You will go home with far more, properly production panning than you will running a sluce, ever! And you don't need to clasify.
This has to be one of the most uneducated comments I have ever read about gold recovery! There have been millions of dollars put into gravity separation. From large gold mining companies and small scale retail producers. Using closed circuit tests and real science. It is true that gravity separation has its sweet spots for optimum recovery but, the fact is you have to set up a sluice pretty wrong and feed it very wrong to lose 30 to 40% of the gold that travels through the box.
Most small scale especially beginning in stream prospectors run so flat and feed so slow that they could never get below 80% recovery. They don't realize they could have more drop feed more and still have 85 to 90 % recovery plus move more material.
I would rather have 80% recovery of 25 buckets of good material than 90 % of ten slow buckets. But, like I said you have to be just plain bad at it to come close to losing 30 % of the gold you dig out of the ground. The newbies lament of " Well, my samples were great but my box must not be working right cause I didn't get as much as I THOUGHT I should" is often heard and based on fiction. The reason you don't recover very much gold if your at the sluice and shovel level is because you were just plain digging the wrong dirt....or the only dirt available!
There is truth in the notion that a certain prospector could produce more gold on a given day than a two man hibanker team.....However it would be because of the prospector and not the equipment used.
Lets do some math shall we.....
I take my totally worthless not recovering anything 4" dredge out for a three day run, I recover an ounce( I WOULD ACTUALLY GET MORE THEN THAT BUT I"M KEEPING THIS EASY

)
based on Ol' Mitch's math. That ounce is now 5%....ONE OUNCE OF GOLD......and my extremely inefficient dredge lost upwards of 19 ounces....you see 100% would be 20 ounces.... Ratchet that up to a small commercial op that is pulling say 15 oz clean ups... how much are they losing

?? There isn't ground rich enough to justify your theory on sluices.
Sorry, Mitch there's more for you to learn about sluice boxes.