Minimum impedance was at 800 cps, and it was close to 20 Meg( self resonance ). At 20kHz it was down to ~200k Ohms, with a trivial few kOhm of winding DCR adding to the shunt capacitance.

I am going to use some precision caps to determine two new self resonance frequencies, and plug in to the calculator to determine C_w and L. With these, off to excel and see how the imipedance curve fits the L and C impedance curves.

I measured two samples, and they were indistinguishable from each other on my bench. It was neat to see theory in action, that's for sure. More to come on some other inductors I have as lab scheduling permits.
cheers,
Douglas