If I remember correctly, the PC7 is 750shp and the PC9 is 1150shp - sound right?
PC7s are varied - depends on the model of PT6 up front......I think they start at 550shp.
The ones that I have been acquainted with had a demand O2 system with enough for a single pilot to empty the drop tanks and adequate for two under about 20,00 feet. We did some serious touring.....