I have an old, battered but cherished 1968 Contreras that had become unplayable as age caught up to it. It was a guitar that had no real resale value, but had great sentimental value, (I've had it since 1974), and a lovely tone. A luthier friend suggested a fix similar to Alan Carruths. It involved cutting through the heel with narrow bladed radial-arm saw while the guitar was clamped in a fixture, then making a second cut to square the gap, and inserting a slice of wood. It was glued in with epoxy and wood dust and is almost invisible. The guitar now plays wonderfully, the action and intonation is good, there is sufficient saddle and break angle. He charged me around $350. It also was re-fretted and the fingerboard trued, but that was coincidental to the neck repair. He has performed this frightening surgery on a number of high-end guitars of the same era, (Ramirez, Kohno, etc.).