You can also buy the connectors bare for crimping onto wire lengths of your own choosing.
I've managed to get by with the posted wire lengths so far tho. Sometimes adding a 3" onto a 6" to make the 6" a little longer.
Farseeker is correct, with a little flat screwdriver blade it is not hard to slightly lift the plastic retaining tab and slide the pin out to put it in the correct hole - I've had my share of pinning mistakes
If you get the pin in the crimp housing in the wrong orientation, it just won''t snap into place. Pull it out and rotate it 90 or 180 degrees and slide it back in.