I would switch the order of DH1 and DH2. A tone argument is very rarely relevant to the substantive dispute. In most cases, the tone of an article shouldn't lead you to update your belief in the conclusion. An ad hominem argument, on the other hand, is often substantively relevant, especially given the power of motivated reasoning. It is entirely reasonable to lower your credence in the conclusion of an article arguing that senators are underpaid once you discover that the author of an article is a senator. Of course, if you have already evaluated the argument itself, and are fairly confident in your evaluation, then learning the identity of the author shouldn't significantly impact your belief in the conclusion (kind of like argument screens off authority), but that is true of tone arguments as well.

The justfication for placing tone above ad hominem in the hierarchy is that the former at least responds to the writing, not the writer. But surely this isn't adequate justification. One might respond to the writing in many ways that are entirely irrelevant to the disagreement, e.g. by reproducing the written piece in reverse order. The question should be, which of these responses is more often relevant to a proper assessment of the truth of the conclusion.