I reviewed the latest post at http://aliteraryartistsmusic.com/ and I found that you have manually set the fonts to "font-size: small" for every line of text in that post. You can see what I mean if you open the "OUTCAST WITHIN" post for editing and then look at the HTML tab.
Here is a direct link:
Here is an example of the font size settings currently in the HTML: http://cl.ly/FSEa/o
So what you are doing is setting the size to small with HTML and then trying to make it big again with the Body Text font size setting on the Appearance → Custom Design → Fonts page.
I looked at a couple other posts and it seems some of the posts have the extra font settings in the HTML and some don't. For example, the font size in this post looks normal to me and it doesn't have any HTML setting the font size to small:
What you should try first is removing all the mentions of " font-size: small;" from the HTML in posts that have that. Make sure not to remove any quote marks like " or brackets like > from the code.
Another option would be to use CSS to try to make all of the fonts larger regardless of any settings in the HTML, but then you might have the opposite problem where some of the fonts are the size you want and others are too big.