what is the best way to install a retaining wall using "J-blocks". The company literatue says to dig down 6in. and put down 1in. of granular fill then compact that using compacter. Also compact behind the wall one course at a time with 12'' wide bed of granular fill. The place that sells the stones recommeds using pea gravel base and backfill with pea gravel or small gravel. also use leach pipe. The wall supports a hill that is lawn 40ft. from top of hill to wall and drops about 6ft. The wall will be 6 courses high or 32 in tall, and 40 ft. long. Soil is clay but not heavy. Has any one used these small ''J-blocks" they are everywhere around here.