[Rupert]

Originally Posted by Prince Charon

The Hedge Magic advantage as written costs 20 points, and lets you use the Hedge Magic system. Fine for 3e, but with 4e it might make more sense to treat it as just another form of Magery 0, or not require an advantage to use it at all, just base it on skills. In the latter case, once you get to a certain skill level (16? 20?), you start to understand the higher mysteries of the craft, and can apply the magic of the world to improve the effects of an action; alternatively, you might use a variant of Mysteries of the Trade from GURPS Fantasy pp162-163: (Profession or Skill) Magic is an IQ/VH skill that is used for Hedge Magic, defaulting from Base Skill-6, but without the other rules in Mysteries of the Trade. Optionally, you might get a head start on the higher mysteries by learning various esoteric skills (Occultism, Ritual Magic, Symbol Drawing, Thaumatology, et cetra); otherwise, they serve as Complementary Skills, or have no significant effect. You could also do it as a Realm system, with each skill having its own Realm (far more realms than is normal for Realm systems).

I think a 20-point advantage is about right unless everyone can do it relatively easily it's quite a significant Unusual Background.