Recovery Speed, Sweep Speed and Ground Filters all interact. If you tweak Recovery, you should consider tweaking Speed.

With DFX, Recovery = SPEED not DELAY as with the V machines. If you decrease coil size, you must 1) INCREASE your recovery speed or 2) slow down your physical sweep speed.

To optimize the target signal for that physical sweep speed, adjust the units Sweep Speed setting until you get the best response.

Keep in mind that you need to run 3 filters or more for the Sweep Speed adjustment to be active.

Just play with the settings, holding your physical sweep speed constant until you get two hits with the best response.

You might want to add at least 1/2" to each side of the target separation to accommodate for edge effect, or drop your PAG / AC / DC sensitivity. Its best to do these setups with the PAG / AC / DC settings that you normally hunt with.