Hi Marty, I'm a fan from Peru, we all liked your guitar clinic in Lima, and hope you come back again. This is a guitar technique question. As you have some time talked about modal ambiguity, my question is: To improvise with this technic, do you need to have knowledge of every note in every fret and every string?. If so, do you know about any trick to reach this knowledge (please don't say "just practice")?

There are NO TRICKS in guitar or anything else that you want to do well. Of course you need knowledge of the sound of every note on every fret and every string to improvise well. Yes, this does take a lot of time. Did you really expect a different answer? Does any other worthwhile skill come any easier? The sooner you realize these realities, the sooner you will be on your way to becoming a musician. Best of luck to you, and thanks for the question.