More importantly, you'll never really get a sense of how she handles on a sea trial anyway. At best, you'll only know how she handles in whatever wind and sea conditions exist on that specific day and there may be no wind or too much wind. Unless you've sailed that particular boat before, you'll spend more time thinking about where the lines are than really paying attention to any subtleties. Sea trials are important, but are intended to insure things work that can't be tested at the dock (furlers, engines under load, gps tracking, autopilot, etc). They are not intended to be test drives, like a car.
This is spot on!
Think about what equipment is on the boat that you would need
to test at a sea trial.
My first boat had new sails, and a new roller furler when I bought it. Nothing else; no GPS, no auto pilot, no engine driven refrigeration, etc. The bottom had been cleaned and the keel bolts replaced a week before (but that's another thread). I had been out on demo sail on a sistership a month or so before, so I knew how she should have sailed.
Here is a pic taken during the "sea-trial";
That's the surveyor on the foredeck.
Therefore, the "sea-trials" consisted of bringing the boat from a mooring to the dock, then, running the engine in gear while tied to the dock. We ran the engine up to operating temp, and ran her at WOT in fwd and rev.