Would be smarter to set it up like 1 and 2 as jog wheel stuff, and 3 and 4 as DVS.... for me, it's easier that way.
I just got my DDJ-1000 and notice that when scratching slowly, there's "wobble" or "warble" in whatever sample I scratch. This is not present with Rekordbox DVS and timecode. The same problem happens with the 800, which I also have, as a test unit.
I don't understand why it sounds so terrible. The DDJ-SX's jogwheels scratch perfectly with no audio artifacts.
I tested with RB5, RB6. Same issue. Makes me pissed that I dropped twelve hundo on something that has audio artifacts the older units don't.
Test and see for yourself. Try any "ahhh" sample, or any vocal like "ah yeah" or anything like that.
DVS works through any channel but certainly it's easier to configure with 3 and 4, and leave the 1 and 2 for the built-in jogs.