My take on a sponge holder to fit sponges that we use at home - 12cm x 8cm. It has a slope to drain the water, and small legs (6mm) to elevate the sponge holder so that it is at the same level as a brim of the sink. You can modify height of the legs in your slicer to fit your needs. And then just glue the legs to the bottom of the sponge holder.