I think it is really important to structure faucets like this to distribute a smaller percentage at time of issue and vest over time.
Incentives, incentives, incentives.
If a faucet is created to simply distribute, it will take all of 5 minutes for somebody to create a pathway to claim the bitUSD and trade for USD or bitcoin.
I suggest something like 25% of total if claimed immediately and an additional 5% added each month, which the unclaimed total returned to the faucet upon time of claim.
The initial notice of issuance should be enough to plant a seed - the required vesting will incentivize the user to stay "tuned-in" and hopefully become cheering advocates for Bitshares.
*This structure would probably be even more effective when using BTS, maybe it would be beneficial, if possible with minimal labor - to allow the user to decide whether to accept his karma in BTS or any bitAsset they choose?