Well the NGH OEM carb and pump/regulator unit do work OK. I think people are still trying to have the carb work like a normal carb. It does have issues, but it does work well nonetheless. Most problems are with the pump/regulator unit. You need to use a fuel filter to keep crud out of the carb and pump/regulator. The pump/regulator is sensitive to engine vibration and also heat and it may leak and need some TLC to fix that too. You may need to replace the diaphragms as well. The pivot arm for the fuel inlet valve can get bent down and need straightening out some too. replacing with with a mild steel one from a Walbro rebuild kit works too. Many of the parts in a Walbro rebuild kit fit the pump/regulator just fine.
First here is a pic of what the throttle barrel looks like when the engine is idling. it is open about 1/2 way. But it does work well that way. You can adjust the throws on the servo using a computer TX easily enough. next the low speed needle is about 6 turns out and the high speed is bout 1.5 turns out. yes the carb spits fuel, but that is normal for any IC engine with more aggressive port timing. The fuel spitting does not mean it is too rich on idle. You don't need to change the needle tapers and other mods to the carb.
Here is a short video clip showing that the engine and carb do work and can be throttled at different speeds OK.
[youtube]http://www.youtube.com/watch?v=3Zfeq-B6e3E[/youtube]