Hate to throw water on your fire,
but that grease zerk does not grease the throw-out bearing, that bearing is a sealed bearing.
What the grease zerk does is lubes the collar that holds the throw-out bearing, do not over grease it as doing so will cause the clutch disk to become bathed in grease and will destroy it, it only needs greased about once every 4 years or so in our normal working conditions, remember these tractors were designed to work in rice fields and very wet conditions.