James,
I have the same camera but use Canon EF lens. If there's enough light I always use AF but at dawn and dusk I use a my messy combo digital zoom/torch/1 third manual focus method.
I shoot f11 99% of the time for reasons of DoF and reliable sharpness.
If the subject is far away I use infinity but digitally zoomed in as far as possible for fine tuning.
If there's a convenient light source in the near distance (aka ~ 1/3 in any direction) I'll do a digital zoom in, manual focus.
If there's no light I'll do the same thing but use my LedLenser torch to light up something with sharp edges 1/3 into the frame. A rock, tree, whatever.
All of this requires a fixed f stop of course. I also don't stick strictly to the 1/3rd rule. I find anywhere between 1/4 and 1/2 into the frame to work fine but thats with my EF 16-35mm f/4L.
All this is all well and good but I've lost count of the number of times I've forgotten to switch back to AF as the light improves................