I can't give you any concrete advice, but this post claims that the best time is around 2 PM EST.

https://steemit.com/steemit-help/@steemrocket/the-best-time-to-post-on-steemit-infographic

I can't make that time myself, but there are a number of handy-dandy post-scheduling services you can use. Just search them up. Good luck!