Uh, Gary, I don't much like your method of determining the cap value. First, these caps aren't rated at very high voltages, so doing this with the 120v mains voltage could easily wreck the cap -- and tantalum caps are especially sensitive to over-voltages and reverse polarity. Second, being the mains voltage, if the cap does go bad, it'll go out with a dangerous bang and could do some bodily damage.
The idea is good if you use the sine wave output of a function generator or an audio oscillator. The lower voltage and power is safer for the operator and the parts. In addition, you can change the frequency to allow more reasonable voltage readings without using resistors of extremely high values which can in turn give you funny readings because of meter loading.
I was surprised at the mention of telco parts often being custom. I never did understand why a telco capacitor would have a value of 0.02383µF with a tolerance of 5%. The math doesn't hold up very well, does it?
Nearly all caps do have standard values and I, too, regardless of how definitely the colors appear to be orange and red, would doubt the 0.32µF vs a 0.33µF. On these conformal coated tantalums, they often would shift a color a bit so that you could tell that there were two digits shown. That way, you wouldn't have to wonder if the first and second bands were duplicates or the second and third bands were duplicates, which would make a tremendous difference in the value.
The 24 standard values are 10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82 and 91. These are the standard values for 5% resistors. Every other one (10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68 and 82) are for 10% resistor values and every other one of those (10, 15, 22, 33, 47 and 68) are for 20% resistor values. Capacitors tend to use the 20% standard values even though they may have tolerances of 10%, 5%, 2% or even 1%. Usually a cap is used with a resistor for some kind of timing or frequency-determing network and selecting the cap and then trimming out with a tight resistor is cheaper than stocking all kinds of standard value caps.
Dean