It appears that the Font Picker does not have an option to specify class, nor does it appear to apply the conditions properly for a radio button box earlier in the meta sequence.
I would also like a check box on the font picker screen which allows me to suppress the sample box, also, I would like to have a way to setting a class on a textarea input form and then the font selected gets applied to that text input box at the time when you change the font. (I have gotten this to work with very minor changes to your JS and PHP render for fonts, but would like in the product so I don’t have to worry about fixing it when you do updates.)