After you have done your "one to many" comparison on GEDmatch, you can copy and paste the information into MS Word. Change the page orientation to Landscape, set the margins to 0.25 all the way around and set the font to Calibri 10. These settings will make everything format correctly and be readable but you can certainly tweak. If you notice, the check boxes are visible AND usable. This makes a great worksheet to keep track of who you have contacted and which testers you can link to a most recent common ancestor (MRCA).
In the below example I have blanked out the details for privacy. If there is a check mark I know exactly who that person is and how they fit in. I did this screenshot as an example for the blog but my real one is also color coded. If I have contacted someone but I haven't heard back yet, I color code that line red. That keeps me from accidentally emailing the same person more than once.