I tore off some 70s fake lava rock off my indoor filreplace and want to replace it with some cultured stone. I'm starting with the corners and have all the corner pieces. Thing is, I want things to line up perfectly with the (vaulted) ceiling and have a piece picked out that will fit perfectly up there. This stuff is probably too heavy to work from the top down, but I'd still like the top along the ceiling to look neat and perfectly fitted, if there is any cutting necessary I can do it along the floor. Would this work for the corners at least? Place the stone I want on top, mark a line on the cinder block with pencil. Leave a gap, test fit a stone below it and do the same thing. All the way down to the bottom (and keep track of the order of the stones). Then, start working with actual mortar from the ground up, placing the stones as they were pre-fitted. Then I should end up with the perfect piece in the perfect position on top. Does this sound reasonable?