JFET Matching/Sorting

Could someone kindly describe a simple circuit for measuring turn-off voltage (Vgs off) for JFETs (both P and N channel, J210, J177)? Something that makes use of a single resistor and, say, a +/- 11V power supply. The turn-off range for the N-channel J210 is -3V ~ -1V, and that for the P-channel J177 is 0.8V~2.3V. I have a batch of parts of both I need to sort according to Vgs(off) and Idss.

Thanks
Kofi