I read several different opinions of font style and size,
Anyone have an opinion, that's using Thinkific?
It really depends on specifically where on your pages the text is going. But in terms of font style, I'd say that for body text a sans serif font works best. For example, the default body text for most Thinkific pages is Open Sans, 14px.
I hope that helps, but just let us know if you have any further questions.