Thanks very much, Daniel, for that helpful reply + references -- I'll be able to get the job done right, now. As a point of curiosity, though, after I made my original post, a bunch more googling let me to using
3drefit -space MNI
as a candidate fix. In one of your links you give a variety of methods by which the MNI realignment might be effected, and the 3drefit is not among them. If you have a moment I'd love to know how 3drefit fits in the ecosystem if it doesn't do this kind of realignment?
Shane
