Rosemary and Megan,
I like the idea of avoiding a one-size fits all policy, but would want to make the following modulation to what you are saying. I don't know that I would necessarily follow name card practice. That can be based on something as ephemeral as "what someone told me," and not necessarily indicate much of a strong preference, or much self-identification.
I would want to consider several things. One is of course cultural respect. The second is primary area of activity. The third is past usage. Often, we are dealing with people who have been more active (and lived longer) outside of Japan than in Japan. Objectively speaking, the person I know primarily as Murobushi Ko, has probably spent far more of his career being known as Ko Murobushi. So I feel much differently about Koichi Tamano and Ko Murobushi, than I do about Tatsumi Hijikata.
When I was trying to figure out how to treat Ono (with macron), vs Ohno, I sent out a bunch of related emails to a list serve for modern jpn art asking the same question, it turned out that the 'h' in these names follows from newspaper pronunciation conventions, but can be confusing in that if you had the name Ooi, and romanized it Ohi, it wouldn't be clear if the name should be pronounced Oh-i, or O-hi, and in the case of the prize winning author Oe, no one ever romanized as Ohe, even though that would be consistent with the usage. Finally, I just wrote to the Ono's and asked them if they had a preference, or if they had specifically chosen Ohno, and I got back the response that I should do whatever I felt most comfortable with. That was a strange response which didn't fully answer my original question, but did make me think that in fact, they hadn't been proactive about "Ohno" in the beginning, but just ended up there. So I ended up going with Ono with the macron, because I have always felt that "Ohno" suggests too much Munch's The Scream. That is, for me, the cultural respect argument trumped the past usage argument since they didn't seem committed to it, and saw a chance to sway practice.
For butoh/buto, I went with butoh, because the east asian librarian here told me that otherwise people might not be able to find it. And that is important too. You want to be part of a debate, but if no one can find your contribution, your voice won't be heard. In time, there will be robust library of congress headings and cross-headings, and the choice won't matter much.
BB