I think 50 days are fine. As we have time until August 1, there is enough time to promote the new phase. May be it's better to set as 60 days to round it up as 2 months.

I think dropping social media points will be a big drawback to participants who don't have much steemians from their countries.(like me) It may be discourage participants who don't have recruitment ability. The team concept is the same.

I really love to assist participants towards good diaries but also I like to involve the in-game same time. Maybe you can think of a separate challenge to reward the best diary promoter and assistance. :)

For promoting, may be we can simply display a banner under each diary post, or @steemcurator01's comment. Or can initiate a short time event to design a banner, sticker or something by promoting the game.

Further, I would like to suggest to give an additional for novelty, creativity, and social value of the diaries. This will improve quality of content in steemit.

Thank you