Changing lineheights in Styled Text plugin

Can anyone tell me how the lineheight / linespacing could be changed in a custom size, when someone has added the ‘Styled Text’ plugin to a project? I know how to do it with css. But i would like to do it using the user-interface of Rapidweaver. It’s been such a long time ago i’ve been using this plugin. But recently someone was asking how to do it. He is not willing to learn css, so additional code is out of the question. Besides that, he is using so many themes in one project, that it would be nearly impossible to find all the correct selectors. Thanks in advance.