Unfortunately, I have not found much information. On the website of the "Societé Astronomique de France" they say:
A team of researchers from Paris Observatory – PSL under the direction of Dr. Miguel Montargès (author of the study published in Nature, "A dusty veil shading Betelgeuse during its Great Dimming") is mobilizing the amateur astronomer community to acquire photometric and spectroscopic data on this occasion.
The collected data will be used to characterize Betelgeuse’s photosphere in the visible and, potentially, to reconstruct its image and the velocity distribution of the convective cells.
Ref. Occultation of Betelgeuse by asteroid (319) Leona on 12/12/2023 – Press release
I also found: Asteroidal occultations of stars are frequent phenomena but the occultation of Betelgeuse by Leona will be extremely important and unique. It represents an extraordinary opportunity to analyze the diameter and brightness distribution of Betelgeuse’s photosphere by studying the light curve as the asteroid progressively occults the star from different points on Earth and at different wavelengths. In the overwhelming majority of the stellar occultations the diameters of the stars are tiny compared to the angular size of the solar system body that passes in front of them so the occultations are not gradual, but in this case, the huge angular diameter of Betelgeuse will give rise to a different phenomenon of “partial eclipse” and “total eclipse” (provided that Leona’s angular diameter is large enough compared with that of Betelgeuse).
Ref. The stellar occultation by (319) Leona on 13 September 2023 in preparation for the occultation of Betelgeuse
The "International Occultation Timing Association / European Section e.V." made a Call for Observations: Occultation of Betelgeuse by (319) Leona on 2023 Dec 12
And they have published on their website a follow-up of the occultation: News Feed – Occultation of Betelgeuse by (319) Leona
This Spanish website invites amateur astronomers to make observations of the occultation: La ocultación de Betelgeuse del 12 de diciembre de 2023
The dimming of Betelgeuse due to the occultation, captured by an amateur in Spain this past night, can be seen here, (Betelgeuse is the bright star at the top, a little to the left).
Occultation of Betelgeuse (Betelgeuze) by 319 Leona (Jörg Schoppmeyer)
Best regards.
UPDATED: Light curves and videos of the occultation are being uploaded: Observations of the Occultation of Betelgeuse by (319) Leona (IOTA/ES)