It will be my sensei who is testing me, and I know he has very different expectations to most people in the organisation. I think I will be more comfortable doing what he wants that with meeting the expectations of anyone else in the organisation.
Speaking as someone who has taken sandan and been awarded yondan from a Yuishinkai affiliated group then I would simply suggest you demonstrate your own Aikido. I class my own teacher as Hiroshi Ikeda sensei however ASU don't have any internationally affiliated Dojo's (yet) and so my dojo is a member of one of the Yuishinkai affiliated groups. I don't do, and never have done 'ki' Aikido - in my own grading I was performing techniques as I do them and not how most of the founding members might choose to perform them. The only thing I'd watch out for is taking care of your uke, if, for example, you have a preference for something like Koshinage and the dojo you're testing with doesn't perform it often (just as example, I'm not saying nobody in Yuishinkai does koshi waza).
Basically, get up and be yourself - when you're under pressure you will soon revert to what your body knows anyway. If anything, Yuishinkai seem to be a very open minded bunch so I'm sure you'll be fine.