Typical tremolo speed/rate frequency range:
0.1 Hz - 10 Hz
Higher frequencies will start to sound like actual tones and not tremolo pulses (source).
Classic rock BPM is probably around 120-160 bpm or so (1/4). If the tremolo is supposed to roughly follow the 1/8 tempo you'll end up around 4 Hz (but you may want to go a bit lower to match a triplet 1/4 feeling).
As for the vibrato tonal range or width - you can't specify that in a general Hz range, as the range changes logarithmically. I will specify that in cents instead.
Most vibrato/modulation ranges I have worked with goes from:
0.. +/- 100 cents (or +/- one half step)
Some models go to a full step (i.e. +/- 200 cents) though. To avoid too obvious disharmony it is preferable to modulate < 100 Cents
A value of 33 cents is probably not way off - it will make the tonal change noticeable while not causing obvious disharmonies.