When should I post?
Well, the best thing to do is post on a range of times and track when you get the best reaction. One person may see your content in the early hours, be bored and share to a friend, then again another may see it just at the right to be able to contact you during working hours.
A bit of context on the post and some testing will help you. Just remember that this is digital so you can easily adjust daily what you are doing.