How much of a distraction did you find my extremely confident probabilities to be from the substance of my arguments?

Very little. It isn't often that such estimates can be considered quantitative anyway. I usually interpret them as 'qualitative with pretty numbers'.

How much did those confident estimates make it seem like I was disagreeing, rather than agreeing, with the LW survey consensus? (It seemed to me that I had provoked people into trumpeting pro-guilt arguments more than they otherwise would have if I had initally given more "reasonable" numbers.)

The distinction I would make between the original and the edit is evaluating vs commentating. This was primed somewhat by an earlier comment and will naturally invoke more objections. It also brings into play the subjectivity and objectivity of probability estimates, as I discussed.

To what sorts of propositions, if any, do you yourself assign probabilities on the order of 0.999 or 0.001?

I usually only assign such probabilities when I am considering myself, literally, as a statistic. There are other matters of fact that I could assign probabilities of that order to but I don't particularly trust my own judgement at that level of certainty so don't usually bother with precise numbers. I certainly wouldn't assign them to any court cases over which there is any controversy. I would say "except if I was the alleged protagonist" but, as matt pointed out, I probably can't assign that probability even then except for the obvious rhetorical purposes.