I actually got around to making the “bias-socket” today.
I used a goldplated DIP8-socket, that I used the dremel to widen(correct word?) a bit to make room for the two resistors. In my case 2,67Kohm 0,25W metalfilm with 1% tolerance.
Using another DIP8-socket to keep the pins in place as the plastic got hot when soldering I then soldered one resistor between pin1 and pin4, and the other between pin4 and pin7 on the “bias” socket.
Please excuse the poor quality pictures.
With +-15V rails this socket should bias the opamp to about 5,6mA
15(the voltage) divided by the resistance(2670) gives: 0,005617….A = ~ 5,6mA.