GSD attack and training..advice?

Nope, because I refuse to give any advice on the matter. You do not know who you are speaking to or what they will do with your information- and with body language and tone erased when you are not actually SPEAKING to them, a single misread word can really do some damage. Plus I know next to nothing on the subject anyhow. So I always say contact a PROFESSIONAL trainer who can help them out.