[NTG-context] is it possible to define \tfxxx and \tfxxxx?

Hi there, after reading the reference manual on font switches, I still have a question. For my presentation I need to use a default higher font size: \usemodule[simplefonts][size=30pt] But given that \tfx and \tfxx scale the font to 0.8 and 0.6, I would need to scale the font also to 0.4 and 0.2 (at least to 0.4). Is there any way to define the \tfxxx? Many thanks for your help, Pablo -- http://www.ousia.tk