So far I've looked at about 10 planes of various types and my rules are
1. it must be ready to fly
2. it must have a current condition inspection
3. it must not have any tangled ownership registration
4. the engine must start before I put down a deposit
4. the owner or someone he designates must take it on a demonstration flight (I do not actually have to be in the plane when it flies) before I close
So far, none have met those rather straightforward criteria.
John, those are NOT unreasonable requirements...astonishing you are finding it difficult, but I can believe it. It really is something that of 10, they failed using this rubric. MM