The Burgess lists I have not seen before. I don't understand them either. What does "Duncan T writer qua merchant as yr son to Duncan T at Luss 1810" mean?
 
To be allowed to trade you had to be a burgess ... [ie from freedom of the burgh] You either qualified by being son of a burgess, marrying a burgess' daughter, by right of completing an apprenticeship to a burgess or simply by buying this right.[ not cheap I think]
so ...
Duncan Turner was a writer [lawyer?] and a merchant who qualified by being the [younger] son of Duncan Turner at Luss. Accepted as a burgess in 1810.