2D and 2 1/2D is what the Standard aircraft handbook says as well, however it seems to be much more conservative than Vans rivet MIL spec, and the 1977 Mil spec.
Since my issue is a single solitary hole, and not a hole line of new holes I figure being less conservative is ok. If I reference the MIL spec on Van's FAQ page, then I am all good. However If I reference the original 1977 version then I have an edge distance issue.
I'm trying to figure out why the two MIL Specs are different, and which one is correct.