hey, i experimented with several techniques when working with doilies, tracing, carving, shellac. the one that work the best i found was actually tracing the pattern directly from a doiley, and then waiting until the piece was bone dry before i started carving. i would spritz it with a little water and then carve using a hoop or dremel tool.
shellac also worked really well, but you need a thicker doiley. you paint the shellac over the doiley, using it as a stencil, and then wait for the piece to dry. then you can go back in with a sponge and start to wipe away the clay that isn't affected by the shellac. it will leave a raised pattern of the doiley. hope this helps! sorry its been so so long since i've been on here