In reply to RobJP:
I'd go with what ablackett says.
We did the northen half from Vizzavona S-N with three unfit teenagers in 9 days, on no more than 4-6 hours walking per day. You'd spend much more on getting to and from Corsica than on the refuges, so I wouldn't worry about the cost of them. It's a footpath, so way less technical than the Cuillin Ridge and eminently runnable 99% of the time. Even the Circe de Solitude is a doddle.
However, you can throw in more "technical" bits all over the place as variants or asides, like the Paglia Orba by the refuge Ciottulu di i Mori, where the service is with a snarl, but the coffee is the best on the route.
It is also really beautiful, and I'd like to go back and do the southern half, or all of it, sans teenagers (we haven't got any now, anyway!).
Post edited at 15:58