G'day Mate,
I have an 8Ft senior Telemaster, & it will take off & fly at less than half throttle, with a 60, so a 160FX will fly your 12Ft at just above idle, well maybe not, but it should have way more power than you need.
I have a 160FX, & I use 16 to 17x10 APC's on my aerobatic planes, you would do well with about a 20x6, remember that the 160FX is flat out at 9,000 to 10,000 RPM, so prop it accordingly.