Heli had nothing to do with the choosing the Baron, I think he may have been at Aerial Tours at the time. The first Baron came in 1962 (?) and was Junior's decision, along with McCook. TAL only had that first Baron a few months when Brian McCook departed Minj (or Banz) for Mendi, when, unbeknown to Brian, a main wheel fell off. One of Peter Howard's labourers found the wheel in the grass, Peter contacted FS Madang and Brian was diverted to Goroka for the first Baron wheels up.
I have no idea how many Barons TAL/Talair owned in total however I do recall the maximum number on the register at any time was nine, tending to confirm High 6's estimate of 15 could be correct as I suspect the insurance company bought at least six over the years.