Any ideal when SCCA will determine what rain light meets 2024 GCR and were to install on Spec Racer?

Class specifications supercede the GCR, and the SRF/SRF3 rules call out a specific size of light and that it can be incandescent or LED. So for now, no change.
Of course, the CRB and BoD could change that rule as well. Or Enterprises could come up with a brighter, flashing light and make that the spec part.
My personal opinion is spend the $15 on a LED light - it is brighter and less likely to fail. I did..