The SC LWV exemplifies the role that leagues can play. In this case, it’s mostly positive but importantly, they share their criteria: “… ratings from Dave’s Redistricting App indicate that the map submitted by the Senate staff improves on the current level of proportionality and achieves a ‘good’ score on that measure.”
LWVSC notes that only 5 (versus 151 currently) voting precincts were split, and county splits numbers haven’t changed much. Importantly, they point to one county split that does egregious harm to minority candidates.
Dave’s Redistricting App is hosted by the leading group, Princeton’s Gerrymandering Project: https://gerrymander.princeton.edu/reforms/WY