Is it Kapton wired? It certainly Is! As Kapton gives off copious volumes of carbon monoxide as it heats up, and as a lot of the electrical terminals were behind a panel which was right next to the airmix hole of the oxy regulator, the first action if there is any electrical problem is to select 100%. Kapton wiring is what led to some of the aircraft having to be re-wired as a reault of the aforementioned too tight loom securing.
Oxy endurance could be less than aircraft endurance in some situations. If you used a whole fuel load of 550kg at low level where oxy consumption was highest, you would get an oxy master warning before you got to your destination. As only two thing set off the master warning, oxy and a fire warning, it certainly got your attention!
As to the PC7 versus the Tucano, the Tuc would win hands down IMHO. The PC7 has about half the power of the Tuc. It's the PC9 which is the Pilatus equivalent of the Tucano. A lot has been mentioned about the comparisons, but they are essentially very similar aircraft. I've flown both and there is little to differetiate them.