We have done 2 lockdrops with ETH. More than 150,000 ETH had been locked on our smart contract in 2 months. We issued tokens based on the opportunity cost and operation costs. Our lockdrop is NOT an ICO or investment but a sort of staking. We never did a public sale!
At the time of writing, only 1000 days participants couldn't unlock ETH. 1000 days lockdrop participants have 7 months linear vesting with 10% initial allocation and other participants have 15 months vesting with 10% initial allocation after the launch.