You are correct that the translation of "kl" as "feasting" is problematic, and "measuring" may be involved. Still, the Gezer Calendar has no observable link with the Torah's cycle of holidays. All it mentions are seasons of
agricultural works. Now, it is true that agricultural works, being as they were the basis of ancient economy, are mentioned in the Bible (e.g., in Ruth 1:22). Moreover, some passages in the Torah present the cycle of holidays as dependent on the cycle of agricultural works (e.g., Exodus 23:14-16). Yet,
the Gezer Calendar shows no awareness of the cycle of holidays.