Paul,
thank you, that is helpful, so Sticky Mat is still thicker than Oilboard mmm... thing is I come out with an idea to keep Oilboard flat and adhered to a flat surface with out adhesive, well almost, I have a rotary engraver and I have a sticky mat ( a different sticky mat, some goes with the name of Multi Mat) to hold things flat and in position, this are reusable you just keep cleaning them up, so I thought I could used it to hold the Oilboard flat and maybe just use painters tape in the edges of the long sides just to hold it so the transfer material that you use to pick the stones up don't lift the Oilboard pattern from the edges, hey maybe it would work?
Ruben