I'm using DuPont cables a lot for my C64 projects but unfortunately, the original connectors are 2.65 mm wide and therefore won't fit to the 1/10 inch 2.54 mm connectors side by side.
It's basically just one part but I've printed the second connector mirrored because the DuPont cables are made that way and so it fits perfectly on each side without twisting the cables.
I've printed this connector standing because of the little notches that are holding the crimp connectors in place. They would come out too flat when printed flat on the bed.
A layer height of 0.2 mm works well, 0.1 mm may produce stronger notches, depending on the material used they prone to break out easily. I've used PLA on a non-heated bed, therefore the first prototypes (as seen in the pictures) came out with some warping. The final version was printed with 3 mm brim and reduced speed and came out very well. Depending on the quality of the DuPont cables the connectors may fit a bit tight.
I've modelled this in Fusion 360, basically out of one part and copied it 18x. Added the boxes to the sides to make it a bit wider and a box for the missing pin. Exported to Cura.