Resources and Shadows from the 'Future Tense' game site brings up guidelines of play with the caution:
There are a couple of ways to approach this for the GM. Everything should grow out of the results you expect for your Players. Call that genre, style, or just 'bias'— you need to imagine the idealized results before you can inform your Players of how it might work.
Here's my base assumption: a handful of people can use a search engine and get something of what they were looking for. With practice, those numbers change. But somehow, One person in several handfuls will get almost exactly what they were looking for— and One will get nothing but junk— though it may be interesting or inspiring junk.
Perception. Pattern often uses your own perception. Search engines use the elements you give them that you think are important to what you want back. If you don't have the perception to know how Morganstern is a great steed— you can't imagine/judge the qualities you seek.
So while most royals could imagine they want a steed that can run a hundred miles an hour— they might have trouble perceiving how that is going to work, or how that is going to work safely. You can be sure that most requests are unknowingly limited by personal safety. Or not.
So in my games, when you buy your Attributes, you are also buying your Perceptions. High warfare folks have better perception of how to use things to better conflict. They know the combat training they want the steed to have. High psyche folks know intuitively how they want the steed to think and respond. High endurance folks have a gut-level surety of how the steed will soak punishment. And high strength royals will know the construction, measure, and physical parameters of the steed.
What you find reflects your own strengths.
So how do you find things to support your weaknesses? Or how do you find something new, something difficult to imagine? Such as a solution to a problem you've been unable to solve.
Go find an expert. A person. Oberon went looking for head doctors when Dworkin seemed to be insane.
And how do you identify an expert for something you don't know as well yourself? Darn good question. First answer I like. Roleplay. Meet them. Talk to them. Figure out if you trust them.
And there is the Rule of Three. Explain to the GM what this info person is going to know that you don't. Rank your needs.
1. Great Success treating insane genius
2. Willing to dump schedule for very difficult case
3. Can leave for distant country and adapt to Amber
And story adventure should flow from that.