The larger of the two veiners can be used to make medium sized leaves also. Instead of cutting at the edge of the impression made by the veiner, cut inside the impression.
There are other Rose leaf veiners available: Franks Rose, Fat Rose, Rosa Rugosa and Burnet Rose.
These veiners, as with a lot of the veiners available are not restrictive in their use, and the image below is of "Creeping Jenny" a native garden plant. The leaves were made using the splat method in various sizes, and then veined with both sizes of the Briar Rose leaf veiner.