I can change Thunderbird's (24) font size for the menu and menu items with the following in userChrome.css. But what does not seem to be effected is checkbox'd menu options. For example you can select "Edit -> Favorite Folder" to select your favorite folder, and it now has a check beside it in the menu. These items are not effected. Does anyone know what the name or ID of these type of menu items are so I can change the font size to 9pt for them too?
.menubar-text { font-size: 9pt !important; }
.menu-text, .menulist-text, .menuitem-text, .menu, .menubar { font-size: 9pt !important; }
#menubar, #menubutton, #menulist, #menu, #menuitem { font-size: 9pt !important; }