Time Pilot,
Actually, having to "debur" the inside of the carb barrel is pretty rare for most engines, as is having to worry about air leaks around the bearing or the backplate.

Get yourself and OS 46 FX (or AX), or a Thunder Tiger 46 PRO, or an Evolution 46, and you won't have to worry about that stuff.

You WILL need to learn how to tune one of these things, but it's really pretty easy once you've actually "heard" someone tune one. Until then, all the written advice in the world can't quite describe the sound you need to hear when tuning. []
Dennis-