There's a simple trick to making the posts in your editor reflect how they will look in your store. This way you don't have to preview the post so much.
Go into the module and click on the blogs tab, open your blog, then open Content Extras.
In the last section, <i>Insert the following into the Redactor JS call:</i>, add the following line:
This will override the stock editor styles and use your store styles. It might not be 100% perfect but it will look quite close to what you'll see when you view the post in your blog.