I am the descendant of the Rymer Waddell marriage. Alexander Waddell was Archibald's father and he was the writer, and so was his father George (one of their notebooks is in the Scottish archives) Archibald Douglas Waddell who was Elizabeth's second husband was a baker by trade.
I have managed to trace back into Bristol slave ship captains named rymer, whihc explains much of how they may have come to be in the West Indes, though Liverpool was another major slaving port. There is a will for a Bushell Rymer a mariner of bristol dated 1745 who seemed to be a privateer/pirate judging by his will. maybe it was the prizes that the rymer mariners won that enabled them to buy ships.