At this point, focus on developing proper stropping technique. Any of the leathers from SRD, or any of the other reputable strop makers, will do an equally good job on your razors. Leather preferences are primarily subjective, based on what one likes in terms of feel, draw and feedback. Almost all newbies ruin one or more strops. There are some quality inexpensive strops which are ideal to practice on while you develop your technique. These will do an equally good job on the edge without you being so concerned about nicking them. Once your technique is better you can enjoy your SRD or other premium strop.