Wow this sketch is on point! Really fantastic job here! I don't remember where I heard it, but someone really good said in a video for portrait painting, you basically get 10% more accuracy on likeness for every 100 portraits you do, so it takes about 1000 portraits to get to about 90-95% likeness. So personally I don't sweat the likeness to much. That being said this looks really awesome and I think you did a great job!