I am now matching J271s prior to populating my amp board. Unfortunately, it is not yet obvious to me how to test for IDSS from a schematic and so, in my search for a guide, came across Tangent’s instructions at http://tangentsoft.net/audio/opamp-bias.html ( bottom of page), which I followed. Below is a pic of my matching setup. I am using a brand new Energizer A23 12V battery with the positive side connected to the jumper. When I measure, I connect the positive lead of my DMM to the JFET’s drain and the negative lead of my DMM to the negative side of the battery. I am certain that my DMM leads are connected properly to the meter and that the meter's settings are correct. However, I’m telling you all of this because I'm surprised at my results and so wonder if I've done this right. Out of 20 J271s, I only have 6 whose IDSS measured above 10. Their readings are: 20.75, 14.18, 12.76, 12.72, 11.13 and 10.48. (I subsequently used the second new battery that came in the pack to do another reading of all of JFETS. The results were all very close to the first readings -- generally within 5 to 15 one hundredths of a milliamp.)
So, gents, am I good to go with 12.76 and 12.72 on one side and 11.13 and 10.48 on the other? Or have I done something wrong to get so many low readings?