No system is going to have complete recovery.
I am happy with about 90% recovery. Unless you're on a huge paystreak, chasing after the last 10% is just not worth it. I've spent many an hour rechecking, re-re checking, re-re-re-checking my cons to get every last speck out, but this hours and days worth of effort was not worth it. I would take the gold I found, and it would not even trip my scale which reads .01 grams. Sometimes, I would go through again, and get only a fly speck or two.
This is the way it was told to me. Would you rather get 95% recovery using a wet system, but only run a 1/4 ton a day, or would you rather run 4 tons a day with a drywasher and get 80% recovery. At one ounce per ton, and gold at 1500 an ounce the recoveries would yield:
95% wet recovery for 1/4 ton you get $265 of gold
80% dry washing recovery for 4 tons will get you $4800 of gold
For my desert area with recirculating sluice versus using a drywasher, the dry washer pushes so much more material, but will not have as good of a recovery. If I find my paystreak, I will be using a drywasher.