Do yourself a favor
Lose the cheek blocks completely-all they do is give you the chance of havimg a poorly led reef line. They must be located VERY precisely to work properly.
The best way is to take the reef line as it exits the end of the boom, go right up to the reef point(s), and then come straight down and tie around the boom with a bowlne or reef knot. If you have a loose footed main, it is very easy to do this (obviously). If you have foot slides, you can also do this easily-tie the reef line around the boom between the sail and the boom. If you have a foot rope on the sail, you can just cut an 8" slot in the foot about 1" up from the rope(and directly under the clew reefs). When you have time, take the sail to the loft and have the sailmaker sew a pece of webbing (with a matching slot) over the cut away material as a reinforcement.
The advantage is that you now have a self-adjusting reef line-it will naturally tighten up with the correct ratio of leech and foot tension-leaving you with a properly reefed sail. I have seen more mainsails damaged from having those blocks improperly located...also, you can do away with the weight and windage of the whole silly system.
It may seem "too simple", but it is what all the newer boats are doing!!
Enjoy!
S