Don’t read too much into the minimum size +/- 0.1mm. I’m on the committee for the AFG’s 2020 Annual Comp and raised it with the official concerned. His view was that if we change the +/- 0.1mm people would be confused because they are so used to seeing the tolerance it expressed that way.
Minimum size means the minimum size stated with a tolerance of 0.1mm (e.g. size – 0.1mm is accepted).
The Australian Facetors Guild has a forum on its website where we raised some of the mistakes you saw corrected. Like the USFG, you’ll need to create a login before you can contribute to the forum, but feel free to do so. I’ve always proceeded on the basis that if you don’t know maybe someone else doesn’t know either and asking the question helps build everyone’s understanding.
The address of the forum is https://facetorsguild.com.au/forum
When measuring minimum size, be careful to read the competition schedule and measure the stone as the schedule says. This year one of the entrants in the AFG 2019 annual comp measured the minimum size using the direction of W on the gemcad diagram only to find the correct measurement was under the local rules the shortest distance across the outline (flat to flat and not point to point). The IFC committee made a set of rules in the competition schedule and they are not necessarily the same as the Australian local rules in all respects.
One example is that the minimum size on the Zircon is measured across the longest axis of plan view , instead of the shortest distance on the outline traditionally used in Australia.
May the best team win.