May I suggest that you update the plugin so that it demonstrates not only a radio button, but any other input type that might be available (assuming there are any more).
Also - I see that a few of the fieldsets have unique classes where you styled the font-size smaller (ie, sect_opt). Perhaps the css could have a class for just that purpose... ie <fieldset class="smalltext sect_opt"> and place the smaller font size on .smalltext instead of .sect_opt?