@leogrowth, understand that you want to grow your user base and following but I'm not sure setting a requirement to reblog your post is the way to do it - there is nothing more irritating than getting a feed full of reblogs. The reaction is often to unfollow and mute the account that does that and the account reblogged.

A much better idea is to ask people taking part in the power-up to write a post about their power-up, include a link to this post and link their post in a comment here. Even better if they write the post in another appropriate community like silverbloggers to get to a wider audience.