Glad you like the lesson!
One of the things I focus on in that lesson is the use of pentatonic scales and how to "follow the chords" or "outline" the changes using pentatonic scales only. (I also talk a lot about that in the lesson "Country Guitar: Soloing Concepts".
So what I propose you try is, if you have a progression like a I IV V, in the key of C for example, it would be (two bars of each chord):
C / C / F / F / G / G / C / C /
You can play C major pentatonic over the whole progression, and it would sound good, BUT, if you try and play C major pentatonic over the C chord, and then F major pentatonic over the F chord, and then G major pentatonic over the G chord, you'll notice that this will outline the changes much more.
Did you try that concept yet?
When I create solos I use all the knowledge that I have, and it's from experience, years of transcribing my favourite musicians solos or licks/lines, and I've had many good teachers that has helped me to learn how to use the different scales and arpeggios etc. So I don't have a short answer for the last question.