Is there an "American standard wire gauge"?
I tried AWG first but the ratios were all wrong. We know from the photo that 1/3 of 00 gauge should be about 10.7 gauge, but that doesn't even come close to AWG.
British or Imperial Standard Wire Gauge does have the right ratios, as does Birmingham and Stubbs, but AWG can't be right. In the middle range a lot of gauges were fairly close to BSWG and I can't really rule them out either.
Tim.