It would not hurt at all to double that rate on a half acre. Easy button, just get a 56lb bag(1 bushel), and spread the whole thing on a half acre. LC recommended 50 to 80lbs of rye AND 50 to 120lbs of oats per acre in his grain mix, so if not using oats, we would always double the rye to 112lbs per acre. It always worked great for our needs. The 4lbs of clover should be fine.