The easiest way to  be sure that the new sedum match your existing sedums is to propagate new plants from your existing plants. One of the many ways that you can propagate sedums are by  divisions , stem cuttings or layering. Divide sedum plants with knife and pull apart. Set them it high in the soil.  You can root sedum by cuttings.Use a clean razor blade to remove cutting just below a node . A node is where the leaf attaches to the stem. It is best to take a cutting with at least four or more nodes. Remove the leaves from the bottom two nodes. These nodes will be the site of your new roots.
  If you want to layer a sedum you can bend a branch down to the ground and cover part of the stem beneath the soil. The leafy end of this branch should be above ground for it will be the top of the new plant. Spring is the best time for layering. Keep soil moist.
https://extension.psu.edu/programs/master-gardener/counties/chester/how-to-gardening-brochures/propagating-by-cutting-or-layering
https://extension.umn.edu/planting-and-growing-guides/dividing-perennials