Are you familiar with the rain bot there?
Nope, what's that?
When you have a chance, have a look at the bleutrade chatbox. You'll notice every 5 minutes there are rains of free coins. That is done by a bot called "rainbot". It accepts donations from the exchange direct transfer function and then redistributes 5 random coins to 5 random users chosen from the last 100 that were using the chat.
That could be an alternative idea for distributing small amounts of coins to a large base of users. Also a good strategy to make the bluetrade traders familiar with GRF. Just keep in mind, when GRF is picked, the bot redistribute the whole balance to 5 users. So... better to donate small amounts often than a big amount at once.
Small donation to people who don't know the project could be a promo, it may also help to start the doge and ltc markets, while giving big amounts may just result in a immediate sale thus affecting the price is a negative way. Supposing we want to keep a target price per GRF around 500 satoshi, I would not donate more than 0.5 GRF per time (each of 5 users will get 50 satoshi each) and maybe it is already too much.
There's another bot there that allows to drop small amount of coins in a longer time frame, but I think it need to be configured to set the amount of coins to distribute at every rain. If you ask to somebody of the exchange staff in the chat, they will be more than happy to help configuring the system to fit your needs.
This could be a nice promo tool to highlight the coin. Worth the time having a look. My recommendation, in case you want to try it, is to understand well how that work before starting, so you can arrange the best possible strategy for GRF. I know many devs who are using that for their coins, so I'm more than happy to share my experience to support the coin. Any question, feel free to ask.