I'm see a lot of hype, but no substance. Generally, on well used carbs the bores for the throttle shaft(s) will wear egg-shaped. Vacuum leaks become serious. Where a new throttle plate assembly is not available, necessary to use a small, jig bore to pic up on the original center line, and bore over size. Index to the opposite side and bore in perfect alignment. Lathe turn a bronze sleeve, slip fit into the new bores using Loctite. Finally, ream the bronze repair sleeves in place for .0002 clearance with new throttle shafts. Any less is just aesthetics.