Earth induction sensors like your cadence (and speed) sensor don't care whether the unit faces in or out. Just be careful of the clearance between crank and chain stay, or foot.
I'm not sure it's critical where it's mounted along the crank. I've used older magnet type cadence sensor (ANT+, mounted to the chain stay and crank) and a XOSS earth induction cadence sensor (set to Bluetooth, mounted on crank) to compare on the same ride. Results were comparable. There were more data glitches with the XOSS sensor, which also occurred when it was set t speed mode and wrapped around the hub. I don't know whether that's a quirk of that type of sensor. But it didn't affect the overall ride average or longer segments.