Please come back and post how it goes.

Most GA's will try and fix you up. I'm just not sure they are obligated to-especially in hurried and stressed situations; or they if can't they have no slack to re-seat easily--like a fully sold airplane. Or both at once.

Or, as I once experienced, a very angry woman boarded with husband and child as the last three people on the plane. The GA had told her there were only three seats in three different but close rows. But she went off demanding everybody or anybody move so they could have three together anyway. But the nearby rows were all occupied by pairs of travelers needing to be together--each pair included a medically-impaired person in need of a companion to escort them.