For blocky supports, a value of 1 is a good assumption if they’re built with normal fill parameters. If they’re built using support parameters (and only scanned every other layer) the strength is degraded and should be set lower. For thin-walled, if you measure the support wall thickness with calipers , expect the SYSR to be less than 1, since the skin is a relatively high percentage of the overall thickness. A good guess, depending upon surface roughness, might be 0.75. In general, you can trade off thickness versus SYSR to find something that fits what is actually built… It can be an iterative process.