I know it has been a while since you posted this question…did you find the answer you wanted or did you find a schedule that works for you?
I am definitely in agreement with LaRue. I want to provide quality over quantity even though SEO and Google prefer a few times a week at the very least for posting new content.
So to find a balance, I really dedicate some time to either researching any new or old gym industry idea, controversy, or promotion, a few times a week and then writing about how I would possibly handle the same situation if I was to implement it at my gym. Generally, although I might find a few good topics and spin off topics, I walk away with one post weekly if I try to find feedback in the fitness community.
I hope this helps and you found something that works for you!