@PercyThrillingt --- welcome to the Club. To answer your questions, here is some info you might appreciate.
The CONTOUR circuit is has NO impact to the frequency response when it is in the full OFF position ----- the control all the way to the left.
And regarding your questions about frequency locations around the mid control, here is an approximation. We with all pot controls there are some variances when rotating the control.
9:00-->200Hz; 10:00-->300Hz; 11:00-->500Hz; 12:00-->650Hz; 1:00-->800Hz; 2:00-->1KHz; 3:00-->1.5KHz.
As always I recommend using your ear for fine tuning frequencies to cut or boost.