[JethroKirby]

Sweet! Technically, Ritual Magic requires at least two Very Hard skills - either Ritual Magic (Tradition) plus Path skill, or a VH craft or professional skill plus the Mysteries of the Trade skill associated with it, that's the equivalent of a path skill. This is so spellcasters that concentrate on one Path have to either cast from a steep double default (-6 plus prereq-count-based), or effectively pay double to raise it (2/4/8 points instead or 1/2/4). Path skills and Profession (Magic) skills default to the base skill at -6. So, if your dwarves are only using the one skill, they're technically getting the benefits of +6 to all spells. Plus, if I'm reading that correctly, no default penalties.

To make it book-legal, maybe make Dwarven Masonry a VH skill instead of Easy (and/or defaults from regular Masonry at -3), and limit Stonesong to no higher than Dwarven Masonry. Individual spells take the prerequisite count based penalty when defaulting from Stonesong, and are bought up as Hard techniques. Or see my last post, upthread, for Power Investiture-equivalent narrow styles if you really want all spells to default to Stonesong at no penalty. Or, just ignore the rules for prerequisite count based default penalties - Kromm has said elsewhere that prereq chains are a minor limiting factor on spells, and can be ignored without breaking the game (although that was in the context of regular spell-by-spell GURPS Magic; not sure if he'd say the same for Ritual Magic).

I guess I could make Singing (Stonesong) a VH skill that defaults to Ritual Magic (Stonesong) at -6, seeing as the act of singing is what produces the effects.

Oh and Xenophile, this is one of the best ideas for magic I've seen with 4E. Two thumbs up! :D