Re: what kind of federation?
I am in a small, independent affiliating headed by a high grade and technically excellent Chief Instructor (which is run as a non-profit making organisation). The advantage is there are no politics and our focus is purely on aikido. Also, although I have immense respect for the chief instructor, I can teach the aikido that I do, whilst still exposing my students to the aikido of the chief instructor and associated instructors. i.e. I don't have to pretend to teach what the chief instructor is teaching before I have internalised and integrated that which I think is useful into my own aikido.
We are still open to train with whomever we want externally, so we don't limit our ability to learn from other instructors. I see this as the ideal situation and am very happy with it. As far as gradings go, although the teaching method is undoubteldy different from that of the chief instructor, I grade low grades myself, but occasionally ensure that we are at least meeting the same standard required by the chief instructor by occasional gradings with them.
I would hate to be in a larger organisation with all the politics and also I would hate to have my ability to question and explore aikido as an instructor heavily restricted by other authorities.