Only metal film capacitors with 100 volt or better ratings are used.
Groupings are made, measured and tuned to get the exact values needed.
Each coil is hand wound and measured. AWG 16 enameled copper wire is used with a home made coil winding jig.
When using a 3 digit meter, there is no measurable difference from one coil to the next. The capacitor groups are tuned to the same level of accuracy.
Shown above is the complete electrical system for a pair of Metals.