Use this calculator: https://dnapainter.com/tools/sharedcmv4
http://blog.kittycooper.com/2016/10/text-to-gedcom-using-ahnen2ged/
Blaine Bettinger Relationship Chart
If you have a second cousin match with a tree, try the mirror tree approach
Enter your ancestry username and password
Select Quick and 4th Cousin
Once you are logged in the profile name(s) show up
Click Gather Matches, when it finishes click Gather Trees, when done click Gather ICW
http://blog.kittycooper.com/2016/10/text-to-gedcom-using-ahnen2ged/
Clean up the Match type column
Change every Exact no Death to Exact
Then delete duplicate lines
Remove duplicate trees
Trees with the same name on them = different members same family