That pun...it hurts...
In all seriousness, though, I also find myself torn between the two OCs; there's just so much potential with each of them. Gustave the chef would be great for the more "innocent" character. He's not trying to kill any pony, it just happens. He's lost sight of what cooking is (making delicious new food) and now has a compulsion to subvert expectations and push limits. The less ponies like his food, the more "original" he gets with his recipes, desperate to find something unique.
Gustave the comedian, on the other hand, is full-on psychopath. When the civil war took his audience, he blamed it on himself and began to obsess about regaining the spotlight. His obsession stems less from "I need to be unique" and more from "I need to feel talented again". I'm thinking about giving him another personality (the similarity to Pinkamena is unintentional, by the way) that would violently chastise him for not being funny or when his kidnapped "audience" doesn't laugh at his jokes (which, as has been established, don't make much sense anymore). I like the freedom this character provides, since he's not shaped after Sander Cohen.
If you can't tell, this post was me thinking out loud. I desperately wish I could use both OCs, but I'd probably die from stress. Maybe someone can adopt the one I don't use?