You should expect good fretwork on a handcrafted guitar. Classical guitar players want the action to be as low as possible without the strings buzzing on the frets. Depending on how hard a player likes to play, this action can vary quite a bit. On a responsive guitar the player should feel a tendency to not have to play as hard. Flamenco players may also like a little back-bow under the bass strings for more snap. This is something that the guitarist Sabicas had on his Barbero, according to luthier R.E. Bruné.
The most important part of the fretwork process is the leveling and shaping of the fingerboard. When the neck is under the tension of the strings, it will develop a slight bow towards the bridge. How much depends a lot on the mass and flexibility of the wood used for the neck. In order to know precisely how much bow there is on a neck with the strings on and then simulate that tension on the neck with the strings off, I use a Dan Erlewine Neck Jig. With this device I can dial in exactly how straight I want a neck to be with the strings tuned up, including if I want some more relief under the bass strings, or even if I want a slight back-bow like some Flamenco guitarists like.
I add a slight curvature, or radius, to the top of the fingerboard on my Classical model. It is not as round as on a steel string guitar, which tends to have a 12 to 20 inch fingerboard radius. I use about a 40 inch radius. This helps in the comfort of the fretting hand in the barre position. On Flamenco models I make the fingerboard flat, both because of tradition and the use of a flat capo. If the buyer of a Flamenco guitar wants the radiused fingerboard, this can be done.
Once the fingerboard is ready I can start installing the frets. With the neck fretted I put the guitar back on the jig to level, crown, and polish the frets. This goes pretty fast because the work on the fingerboard was done well. To polish the frets, I wrap fine sandpaper around a fret-file burr on a special handle that I made and sand each fret lengthwise for a smooth surface. Then I apply the first coat of linseed oil. After the guitar has been french-polished, I go over the fingerboard with another coat of oil. Finally, I polish the frets with steel wool to give them a final shine and clean any trace of oil off them.