Has anyone ever worked with the keystone compaq wall block? It's 8hx18wx12d. I want to put some sand down to level it, which the company recommends and the base is on clay. I have already used a jumpin jack and added large stone to the base along with 3/4 and quickrete. Also fabric between sub and base gravel. I am in NH so have alot of movement, will this be OK? I tried setting the block on the gravel base but it is a sob to level. the sand would help out alot. Any expertice would help.