Squark2004,
If the Queenair you are referring to is a ZK registration, then it is operating under CAA Rule Part 91. There are no flight or duty time limitations applicable, nor are there any rules required under part 135 to be complied with. And the decision as to whether it should be a part 91 or part 135 operation rests entirely with the operator. What rule would you operate under for least cost???.
Prospector