You should make the reward attractive by allowing limited numbers people to register but amount of token to be increased from 150 to 1000 or somewhat. I don't see it attractive for me with total supply of 75 million to register for this tiny amount. If you are offering free then make happy others who participate in this scheme.
I agree, maybe you can make airdrops by number of rounds limited by small quantity. And also please add more details on the bounty and their spreadsheets. By the way I just joined the airdrop. I wish we can receive more as we are the early birds joining it. Anyway, Good luck to your project and we wish you success.