R7 ?
Do you mean R8 ?
1V should be OK, as long as you are not overdriving the filter.
30hz to 30khz, is the sweep "continuous" or does it go in steps of (say) 10hz, like you may get from a digital synthesiser?
That sounds correct.
All the pictures you have ever seen of frequency response have logarithmic scales (decibels) on the vertical axis, your scope will be showing linear scales.
Similarly with the horizontal axis, it is common to plot wide range frequency responses on a log scale, yours is probably linear.
Depends on the sharpness of the notch.
Also on the sweep speed, if the sweep speed is too fast, the filter will "ring" and you will miss the notch.
Sounds as though you are on the right track.
Do you have a second audio oscillator?
There is a technique which works with RF when you are using a diode detector to measure the output of the filter/amplifier, but I have never seen it done at AF.
JimB