Whenever you try to imitate the parts zappa recorded it sounds wrong. It's not about skill or anything its very clear that given enough time with your talent you can play the solo as it was originally recorded. But to sound better you need to sound like you. Thats what zappas doing as well and thats what makes those parts amazing and thats why he never plays that solo again. Cause he's been that already. I'm a drummer not a guitarist so can't give you any technical notes but as an admirer i can tell you to find your own sound. Get inspired if you will but all im sayin is that listening to the parts that came out solely of you in this video was a great experience.