I cant seem to find the answer to this question anywhere!
What percentage of guild members do I need to have in a raid to qualify it as a guild run? (normal, heroic)
It seems if I have "just" 10 I need 8 guild members to make it a guild run, but what if I go over 10 people in the raid?
What if it is 11 in the raid, or 12, is 8 guild members then still sufficient to make it a guild run?
Where is the breaking point to when it is no longer a guild run and I need another guild member to acquire another pug?
I'm not sure if it's fixed now, but at the start of the expansion they just kinda didn't bother with scaling at all. In normal/heroic you could get a guild run with 8/10 which is what you'd expect, the standard 80%. However, it just didn't scale at all, you could get the guild achievement with 8/30. I'm going to assume this has since been fixed though so you should shoot for the 80% mark.