I've just started studying and organizing my Liberty Series accumulation, and am starting to think about tagging for the first time -- I always ignored it in the past. Anyhow, I'm confused about tagging types II & IIa. Some references say a Type IIa "completely covers" the sheet, while others say it may completely cover the sheet or leave a "thin" uncovered edge. So what is "thin"?
This first image seems like it must be a Type II:
Is this second image a Type II with the roller a bit shifted, or is it a Type IIa:
PS: I have found some scattered data about what stamps exist with various tagging -- Gene Paquette's articles in the USS as well as "The Liberty Series" by Lawrence Et al. Is there a comprehensive listing of what types exist on which stamps?