We may need to re think the masternode system, how many masternodes are you aiming to (using a quarter of coins for masternodes will get you a max of 200 masternodes... that would be enough?)?

In the case of getting an extra %3, users will get 60 HAL more per year? I don't think that can cover the cost of setting up an extra box for a year (not even in VM scenarios), unless value rises a lot...

Another thing... if we can modify the reward, we may think in another feature... you said masternodes would protect the network, but since you will need a lot of coins, a Deep dive of the value (or great rise), could cause users to drop their coins. So, if reward is greater, maybe there is a way to hold the status of a masternode for a fixed term, let say you set your wallet as masternode, then your coins can't be send for x blocks (to prevent a massive drop of the amount of masternodes).