If you plan on using the rifle for hunting, target knobs may not be the best option. It is much easier for them to be moved out of alignnment. Once you have the non-target knob sight adjusted, it should stay sighted in for the load you plan on using.
I have the standard Williams FP on Winchester models 94 and pre-64 model 70, without target knobes and they work just fine.
Paul B.