As we All know, onboard ddj 1000 fx can be used only on the master channel. But you con simply map djay stock fx.
With midi mapping editor opened, rotate the fx channel select knob on the controller: let’s say we select channel 1, assign midi to “select channel 1” function in “channel 1” section, and so on for every 4 channels.
Then assign the rotary knob for fx on the controller:
In section “selected channel” select fx1 dry/wet function.
Then assign the fx on/off button on the controller:
In section “selected channel” select fx1 active function.
You can also map the rotary knob for fx type selection on the controller to switch through different fx type for fx1.
I’m not in front of the controller as i’m writing, I may have made some mistakes in sections definitions, but i’m sure is clear enough 
