Hi Duncan,
The dynamics of solar eclipses are very well known, although that’s no reason why you shouldn’t measure the obscuration for yourself.
The Observers’ Challenge and the BAA Handbook listed the obscuration percentages for various locations, whereas the article in the October Journal gave the magnitude values (fraction of diameter obscured by the Moon). Some casual observers were put off by the small obscuration percentages, not realising that the magnitude values signified impressive partial phases. I prefer that ‘eclipse magnitudes’ are quoted in eclipse work.
Some teams observe total solar eclipses to measure the Sun’s radius, aiming to determine any evidence of long-term change in its diameter, e.g.
‘Estimating the Eclipse Solar Radius from Flash Spectrum Videos’ in
https://www.iota-es.de/JOA/joa2022_2.pdf
(17 MB download)
Cheers,
Alex.