As noted before the resonances had to be tuned to the 29.5 MHz ( or rather 29.485 MHz to match with the Wenzel) and notches to twice that frequency (58.97 MHz).
I tuned these frequencies and remeasured the transimpedance curves . These are in the attached pdf file.
1) The variable inductances on the PCB have a ferrite core which is actually ferrite powder compacted around an iron screw. The screw serves to provide the adjustability. However, being iron, it seems to have rusted and so the cores are stuck. So several of the cores splintered when I tried to adjust the frequencies.
2) The WFS1 had a finger print/smudge on the face of the PD. I drag wiped it with methanol to get rid of it.
WFS1 is ready to go on the table. I am going to work on WFS2 today.