As a reminder to everyone still persevering with original crossovers with the variable treble controls, I measured DC resistance across each part of the circuits today and found unsurprisingly that there was a huge variation between units due to variations in wear with the variable controls.

Where I would expect both to be identical is where the controls are rolled up full where the resistance should be close to the 50 Ohms dictated by the wire wound resistor of that value in each unit. I had just replaced my resistors with Mills wire wounds of 51 Ohms (12watts) and got readings of 51.4 and 51.6 across the crossover circuit, but when rolled back level, one measured 31 Ohms and the other 1.2 Ohms! Proof if any was needed, that the old crossovers are let down by the treble controls, which are only any good if taken apart and thoroughly cleaned up which is a PITA of a job (a day per unit).

Good job I hadn't gone to the expense of replacing anything on the originals except for the large value resistors!