An alternate method to rig the reef clew line discusses leading the reef clew line over the leech of the sail and back onto the same side. This will ensure that the sail is pushed out like a window blind during reefing rather than getting bunched up under the clew line.
You can see how the clew line is led through the sail and up to the clew reef cringle, back over the leech and through the reef block on the boom. This will ensure that the sail is kicked to port as the sail is reefed and the vertical sections of reef line will shield the sail cloth from getting pinched in the reefing system.
The downside to protecting the sail in this manner is the leech will suffer from chafe as the clew line will constantly rub this area. This is easily maintained with a chafe patch (a sacrificial piece of sailcloth placed in an area of wear that can easily be replaced while protecting the underlying sail).