sorry I had missed the question Michael.
the Bb is great to use on both those chords. so is the G. if you look at the two chords:
Gm is G Bb D
C7 is C E G Bb
see how both chords contain the G and Bb.
anytime you have this 1m to a 47 you can use the pentatonic minor scale over the progression.

your wife does have a good point!
Sit in a quiet room and hit a Bb
on the piano – feel the sound – it
feels like a falling down note.

If you can get to feel how each
note sounds on it own and not
in relation to other notes,
then you will become more pitch
perfect and be able to identify
which note is being played.

i know you don’t want to start the
major improvisation course, but i
feel you would benifit just watching lesson 1 & 2!

I haven’t started lesson 2 on my sax, but i have watched it 4 or 5
times just to see & feel what is
going on, by the end of several
viewings, i was able to pick out
which notes were being played on the sax, and feel the different
effects.

Sounds have many dimensions,
1st – the pitch changing
2nd – the volume changing
3rd – the duration changing
4th – physicaly moving the sound
closer to you and then moving it
away from you (imagine standing in a parade, waiting for a marching
bsnd to come round the corner and
then when it is front of you and then when it dissappears – thats a
different sensation)

Play 1 note & play around with
the last 3 and theres loads of variations!

Theres lots of rules for music that apply, but you. can bend the
rules if it sounds ok, or if
you want to create a specific
effect! Music in horror films,
although boring, shows a lot
of what you can do in music,
which doesn’t sound musically
appealing but does have a dramatic
effect!