I've been building AK for the past 2 years, mostly form Tapco style flats. As most AK builders know, these receivers need some tweaking to make the build function properly. Is this similar to the "adjustments" needed to make an Enterprise or Century FAL receiver work? I'm looking for some reference point for the amount or work required before I buy my first kit and receiver. Also, what about barrel fit? Will I need to have lathe work done to get the barrel to index?