Got the MPF102 this afternoon, checked the pinouts, and decided to twist G and S, so that D is in mid position like the original DGS arrangement when looking at the flat side, the pins down.
Used chromatest's suggestion to add some wire insulator on these two legs. Just twisted them and pushed the transistor so that the tubing goes down to the PCB, the two friction forces (tubing vs tubing and PCB vs tubing) keeping the tubing put.
Just tested the LFO and it worked straight away.