I think I can picture the lift sensor waveform! Can you recall the peak-to-peak voltages you see, roughly?
Next time Xac and I go over to look at Cassy I'll take my old Telequipment S52 'scope with me. It's just the job for those sort of tasks. It's like me, old and battered, but only cost me a tenner
I'll also take my camera and try and get some pictures of the waveforms.