Precise measurement of cable cross-section...

I have a precise measurement project about measuring the cross-section of an insulated cable wire and determining the orientation (offset from center) of the metal core... I am also budget concerned and trying to push the limits of Arduino... Until now I managed to build a measurement chamber (dark inside) and placed 2 CNY70 sensors looking at each other about 70mm apart... When I pass the wire-cable between them I can precisely measure thickness within 0.1mm and also see offset if present... My problem is now to measure the metal wire inside the cable and to determine whether it is centered... I read much about metal proximity sensors but they do not measure distance as far as I learned... Is there any way I can precisely measure the distance from a metal wire within a 5cm distance, so that I can place 2 of these sensors near my CNY70s and measure distance to metal core.. This way I can combine the readings from CNY70s and metal sensors to calculate insulation thickness and offset... Any ideas?

If the cable is not metal armoured then maybe an inductive sensor will do what you want but there are several types so finding one that matches your needs may take time.