Well, that should richen the midrange some, though you might lose some idle mixture quality. It's always worth a try if you are willing to experiment. Wouldn't take much to solder up that notch and dress it round and smooth. I would probably use Sta-Brite silver solder for that.

How about analyzing the acclerator pump circuit and see if there isn't a way to get a bigger accelerator pump shot?

One other thing.... I don't remember the details of your project. What size carb on what size engine? A too big carb will be really hard to get to transition well, especially on a four stroke. Note also that a four stroke generally needs a somewhat smaller carb than the equivalent size two stroke.

AV8TOR