I made the dual color by pausing the print after 2 mm and changing the filament and after another 2 mm i swopped it again.
i used this script in simplify 3d in the script tab and it pauses automatically.

thanks to https://www.youtube.com/watch?v=OiixypnOS8o&t=27s for the script!

{REPLACE "; layer 11, Z = " "\nG1 X10 Y5\nM0\n; layer 11, Z = "}
{REPLACE "; layer 21, Z = " "\nG1 X10 Y5\nM0\n; layer 21, Z = "}\

this worked with 0.2 layers on the ender 3