The ROI is too hard to really calculate at this time because we are getting so many airdrops and none of those airdrops have become worth a significant amount yet but may be worth a lot in the future.

As far as that Chintai market I don't know what ROI anyone has really been able to sustain there. It is new and I haven't tried it.

And yeah if you have to send your coins out then I would be hesitant to try with large amounts.