I took to heart the concept of smallest possible breather hole diameter and have actually gone too small. I did not get git rot flowing from all holes and now I also realise that they will be a huge pain to try and plug.
I am thinking that there was an area within the delam that was "ok" that prevented the git rot flowing past to the "dry" holes so will re drill another injection hole to try and fill it up.
I am now thinking that larger would be better for the breather holes
BTW Git rot gets really hot when you are using it