I'd love to see an example of how you used the chains to hold the tombstones. I really struggled with that this year. I've tried bamboo stakes, fishing line, bricks, you name it. I don't have the carpentry skills to make plywood stones so mine are Styrofoam.
Mine are both wood and styrofoam. The wood ones were easy since they have places to "catch" the chain. The Styrofoam ones were a little trickier. Already having a long piece of re-bar through them, I planted them and then gently placed a thinner chain up and over one or two sides so that they could not twist side to side. The 10" re-bar out the bottom kept them rooted.