Personally.. I don't think reposting a Steemit post to Steemit is a good idea ever. Creating a new related post and referencing a previous post, that is okay and it is good blogging practice.

Creating a post elsewhere and linking back to the post you want to bring notice to, that works and it helps promote Steemit.

So, any repost of a post is spam IMO. You can put your link to the post in the Steem Chat every two hours though.. that is okay.. in the right channel.