I have never been in the military but as to how to attach the patches, I would assume them to be in the same order they would be on a sleeve. I guess it could get complicated if mixing patches that were worn on different sleeves, but there is probably some relative ordering rule out there that could serve as a rough guideline. Based on what I have seen that would put rank below unit, and if worn hash marks below rank.

While I know that the various branches of the military have their rules and most veterans do try to follow those rules or at least the spirit of them, from what I have read there is no actual jurisdiction over veterans by the military in this regard. I have come across two events in my life where somewhat strange interpretations of insignia and ribbon rules were invoked, one by a member of the military and one by a civilian who was trying to harass a veteran. Neither case ended up in any charges being filed against the veterans in question. Just a thought.