Has anyone used the 4" spacers to reach a specific height?  If so, any problems?  Would you use them again?   Since they come as a 4" tall strip without ties, I would place them between the two full blocks at the top of the wall to minimize concrete pressure and attach add'l bracing.  Thoughts?

Evalute the cost and they by themselves look expensive, if the math works and you can use a H/A and a 1/2 block or less to reach the top it makes sense, plus the waste factor was just cut down down signifigantly. If you need to use two rows of H/A the math doesn't work on cost of product but you can save on waste.