The bottom of the net should be about a meter off the ground. If you observe foxes around actively, you can place the nets two meters off the ground, using an extra 5 foot pole. However, your capture rate will suffer, as owls apparently fly fairly close to the ground. If you happen to wake up in the middle of the night, walk over and check the nets again. This is why the nets should be placed within a short walking distance of camp.
Owls use their talons for defense.
For the smaller target owls, the body pluck method will work, as long as you avoid the talons. If you need to use a variation on the body pluck, or if your hands are small, the photographer's grip is acceptable. You can then bag the bird. To get started, it is sometimes useful to place a bag in the talons for the bird to grip, rather than your hand. The talons of larger owls are definite threats, especially Great Horned Owls.