Dave,. I just wanted to comment on the 2-wire vs 4-wire sensing on the R6142. It is common practice to hook the sense leads to the source leads internally with resistors. These resistors are sized so that the sensing error they add is insignificant which is why you didn't see a change in output value. But if you use 4 terminal sensing at the end of your cable, and there is a load there, you will definitely improve the delivery point accuracy by using kelvin connections. For example, let's say the sense and source leads are connected internally with 200 ohm resistors. Then try to source 100mA at 10 V through 22AWG wire. Without the sense leads, the wire resistance alone will cause a significant error. At Fluke we'd debate leaving out the 2T/4T switch as the resistors add so little error in low current measurements.
Obviously Advantest Engineers went with the resistor connected sense leads, so, for low current outputs, you would not see a difference between the 2T and 4T positions of the switch.