I'm currently using the 'minor third' scale on my site muxup.com (mainly because I didn't know what scaling to use and I saw it in use somewhere else). It seems fine, but I've found the headings aren't visually distinct enough if they're not right next to each other (i.e. it's hard to visually distinguish a h2 at 2.488 rem vs an h3 at 2.074rem). Perhaps I've chosen a bad scale, or perhaps I should be adding other visual markers to help distinguish the heading level?