I did it in about 4-5 hours, which is pretty quick for me....I used charcoal, mechanical pencil, 9B graphite pencil, and a black derwent drawing pencil, on A4 size paper.
I show it to him of twitter, and he loved it! He said it was amazing (or more, that I am amazing!)
I will give the original to a friend who is going to see Guns N Roses in Vegas, and she will give it to him for me (as well as a drawing for DJ Ashba)
Hope you like it!