Once the photopolymer sheet is finished I lightly oil it using olive oil. I tend to spray the sheet lightly, rub it all over with my fingers which removes any excessive oil and then if it is a particularly deep texture I sometimes brush into the texture with a flat nylon paint brush that I keep especially for this.
Then I can use the sheet just like any other texture plate - usually by putting my roller guides on top of it, the metal clay in between and rolling over firmly in one movement. If you roll backwards and forwards the clay can shift slightly and you get a blurring or double image so it is important to ensure you do make the roll in one firm action. Once the clay is rolled down to the thickness of the roller guides it can't get any thinner anyway! You can use a texture plate on each side of the clay with the roller guides sandwiched in between.
If I am using the plastic back photopolymer sheet I usually flex it slightly to tease up the edge of the clay and remove it. If I am using the metal backed sheet then I simply tease the edge of the clay up with my thumb and peel it off. Turn it over the check the imprint. Then I usually put the clay onto a small piece of non-stick baking parchment so that I can cut out the shape. Form the piece gently in the usual way, dry and fire.