VGSoff means the gate to source voltage where the device will be "off" if you go more negative, or "on" if you go more positive (in the case of JFETs). In the Fetzer Valve tester, you're measuring the source to ground voltage when the device is sitting on it's turn off voltage. So yes, your positive voltages are normal, and your JFETs are fine.
Check and double check your wiring around the JFET. The black strip on the diode should be pointing towards the 1M resistor and 10n capacitor. Make sure you have a 1M resistor in there. If the diode is right, try lowering the value of the resistor. I'm working on something on the breadboard ATM, and it uses JFET switching similar to this, but I'm using 10k rather than 1M, and everything works perfectly.