[NTG-context] Different fonts for titles

Hi there, how can I use a different font for titles using simplefont? (chapter, section, subsection, ....) At now, I use (e.g.) \definedfont[name:fontname at 12pt], but for many fonts, that results in bad kerning (empty space between characters), but for some fonts, that works. So, is there a better way to change easily the font (using Simplefont maybe), and how to set the title-fonts (no typescript, if possible :)) Thanks! Huseyin