Gosh, I wish I could help you. But I did want to tell you how lucky that I think that you are taking a workshop with Marvin. I am planning on doing that someday. I just have to find a bit of time. He's one of the best there is in my book. Also I plan to take a workshop with Guan Weixing. Those are my two most favorite portrait artists that are painting today.
I hope that someone will help you soon.
