What I've done here is improvise over a 120bmp backing in Am. You can view this as either being pure Amin (A Aeolian), as I'm mostly doing in this improvisation. However, since the backing is largely situated around the G chord, you can also play the G Mixolydian scale, and make both yourself and the listener feel that you are in fact playing in G major. So by all means try that out too! Also, I've tried to vary my vibrato in this improv, to cover both in-time, slower and faster than the beat type of vibrato, as well as the "growing" vibrato and more.
After listening through, get over to the backing track on the next page and give it a try!