I have one and find the same problem.
Here is what I found from my experience with the Turbo Pan.
They are great to reduce your gravel to a concentrate fast and the cost is cheap (around $18 - $26) compaired to the MD (up to about $250).
Trying to pan off the fines at the end is tricky. I found gold flakes in the second top riffle on my first few attempts so I can almost guarantee I lost some gold.
The best solution is to process your materials quickly with the Turbo pan by following the examples on You Tube.
If you classify your dirt into the pan it is important to ensure the riffles are not packed with material, the dirt must be looose.
Clean and rinse dirt then rotate aniclockwise in a swirling motion, this throws the lighter materials off the sides.
Whether processing under water or out of the water is better I haven't worked that out yet as you need a fairly large pool of water to wash the pan under water, something not always available where I go.
The gold tends to work its way into the centre of the pan. They recommend to rotate clockwise at the end, this is to clear the riffles and washing any other gold into the centre. You can check the centre trap for gold at this piont and I remove it at this piont.
This next step is where I find it gets tricky, when I try to reduce the concentrates over the edge there seems to be little to stop the gold going over. At this point I would suggest saving the concentrates in a bucket for further panning in a regular pan.
Maybe its a matter of practice
I did a test panning from a garret gravity trap pan into a container and then repanned the residue in the turbo pan. To my suprise I found two rather large flat leafy flakes (small pickers) trapped in the centre trap in the turbo pan.There is little chance of washing larger flakes out if you check the pan centre once most of the fines are gone.
I think if you are starting out or have poor panning skills (like myself) the turbo pan can be a great asset if the field.
Hope this helps.
